Notes
1. For Part D, premiums include both amounts withheld from Social Security benefit checks (and other certain Federal benefit payments) and amounts paid directly to Part D plans; the premiums paid directly to Part D plans are not displayed on Treasury statements and are estimated.
2. For Part B, includes matching payments from the general fund, plus certain interest-adjustment items. For Part D, includes all federal government transfers, including amounts for the general subsidy, reinsurance, employer drug subsidy, low-income subsidy, administrative expenses, risk sharing, and State expenses for making low-income eligibility determinations. Includes amounts for the transitional assistance benefits in 2004-2007.
3. With the availability of Part D drug coverage and low-income subsidies beginning in 2006, Medicaid is no longer the primary payer for full-benefit dual eligibles. States are subject to a contribution requirement and must pay the Part D account in the SMI trust fund a portion of their estimated forgone drug costs for this population. Starting in 2006, States must pay 90 percent of the estimated costs, with this percentage phasing down over a 10-year period, to 75 percent in 2015 and later.
4. Other income includes recoveries of amounts reimbursed from the trust fund that are not obligations of the trust fund and other small amounts of miscellaneous income. In 2008, includes an adjustment of $812 million for interest inadvertently unearned as a result of HI hospice costs that were misallocated to, and paid from, the Part B account from May 2005 to September 2007.
5. Values after 2005 include additional premiums for Medicare Advantage (MA) plans that are deducted from beneficiaries' Social Security checks. These additional premiums are beneficiary obligations and occur when a beneficiary chooses an MA plan whose monthly plan payment exceeds the benchmark amount. Beneficiaries subject to such premiums may choose to either reimburse the plans directly or have the premiums deducted from their Social Security checks. The premiums deducted from the Social Security checks are transferred to the HI and SMI trust funds and then transferred from the trust funds to the plans.
6. Includes costs of Peer Review Organizations from 1983 through 2001 and costs of Quality Improvement Organizations beginning in 2002.
7. For Part D, includes payments to plans, subsidies to employer-sponsored retiree prescription drug plans, payments to States for making low-income eligibility determinations, Part D drug premiums collected from beneficiaries and transferred to Medicare Advantage plans and private drug plans, and premium amounts paid directly by enrollees to plans. (The last item is on an estimated basis; see note 1.) Includes amounts for the transitional assistance benefits in 2004-2007.
8. The financial status of Supplementary Medical Insurance (SMI) depends on both the assets and the liabilities of the trust fund.
9. Section 708 of Title VII of the Social Security Act modifies the provisions for the delivery of Social Security benefit checks when the regularly designated delivery day falls on a Saturday, Sunday, or legal public holiday. Delivery of benefit checks normally due January 3, 1982 occurred on December 31, 1981. Consequently, the SMI premiums withheld from the checks ($264 million) and the associated general revenue contributions ($883 million) were added to the SMI trust fund on December 31, 1981. These amounts are excluded from the premium income and general revenue income for calendar year 1982.
10. Delivery of benefit checks normally due January 3, 1988 occurred on December 31, 1987. Consequently, the SMI premiums withheld from the checks ($692 million) and the associated general revenue contributions ($2,178 million) were added to the SMI trust fund on December 31, 1987. These amounts are excluded from the premium income and general revenue income for calendar year 1988 (refer to note 9).
11. 1989 includes the impact of the Medicare Catastrophic Coverage Act of 1988 (Public Law 100-360).
12. Delivery of benefit checks normally due January 3, 1993 occurred on December 31, 1992. Consequently, the SMI premiums withheld from the checks ($1,089 million) and the associated general revenue contributions ($3,175 million) were added to the SMI trust fund on December 31, 1992. These amounts are excluded from the premium income and general revenue income for calendar year 1993 (refer to note 9).
13. Includes the impact of the transfer to the Hospital Insurance (HI) trust fund of the SMI catastrophic coverage reserve fund on March 31, 1993, as specified in Public Law 102-394. Actual benefit payments for 1993 were $53,979 million and the amount transferred was $1,805 million.
14. Delivery of benefit checks normally due January 3, 1999 occurred on December 31, 1998. Consequently, the SMI premiums withheld from the checks ($1,512 million) and the associated general revenue contributions ($4,711 million) were added to the SMI trust fund on December 31, 1998. These amounts are excluded from the premium income and general revenue income for calendar year 1999 (refer to note 9).
15. For 1998-2003 benefit payments less monies transferred from the HI trust fund for home health agency costs, as provided for by the Balanced Budget Act of 1997.
16. Certain HI hospice costs in 2005-2007 were misallocated to, and paid from, the Part B account of the SMI trust fund.  See also note 20.
17. 2006 includes an estimated $2,299 million for premiums paid directly to Part D plans (based on 2016 Trustees Report intermediate assumptions).  See also notes 1 and 7.
18. 2007 includes an estimated $2,405 million for premiums paid directly to Part D plans (based on 2016 Trustees Report intermediate assumptions).  See also notes 1 and 7.
19. 2008 includes an estimated $3,157 million for premiums paid directly to Part D plans (based on 2016 Trustees Report intermediate assumptions).  See also notes 1 and 7.
20. In 2008 benefit payments were $237,801 million. Amount shown includes -$8,484 million, which represents a transfer from the general fund of the Treasury to the Part B account of the SMI trust fund for HI hospice costs that were misallocated to, and paid from, the Part B account from May 2005 to September 2007. (The HI trust fund, in turn, transferred $8,484 million to the general fund.)
21. Delivery of benefit checks normally due January 3, 2010 occurred on December 31, 2009. Consequently, the SMI premiums withheld from the checks ($4,070 million, consisting of $3,861 million for Part B and $209 million for Part D) and the associated general revenue contributions ($10,930 million, all attributable to Part B) were added to the SMI trust fund on December 31, 2009. These amounts are excluded from the premium income and general revenue income for calendar year 2010 (refer to note 9).
22. 2009 includes an estimated $3,851 million for premiums paid directly to Part D plans (based on 2016 Trustees Report Intermediate Assumptions).  See also notes 1 and 7.
23. 2010 includes an estimated $4,378 million for premiums paid directly to Part D plans (based on 2016 Trustees Report Intermediate Assumptions).  See also notes 1 and 7.
24. 2011 Includes an estimated $4,990 million for premiums paid directly to Part D plans (based on 2016 Trustees Report Intermediate Assumptions).  See also notes 1 and 7.
25. 2012 Includes an estimated $5,215 million for premiums paid directly to Part D plans (based on 2016 Trustees Report Intermediate Assumptions).  See also notes 1 and 7.
26. 2013 includes an estimated $6,720 million for premiums paid directly to Part D plans (based on 2016 Trustees Report intermediate assumptions).  See also notes 1 and 7.
27. 2014 includes an estimated $7,769 million for premiums paid directly to Part D plans (based on 2016 Trustees Report intermediate assumptions).  See also notes 1 and 7.
28. 2015 includes an estimated $8,657 million for premiums paid directly to Part D plans (based on 2016 Trustees Report intermediate assumptions).  See also notes 1 and 7.
29. 2016 includes an estimated $9,301 million for premiums paid directly to Part D plans (based on 2017 Trustees Report intermediate assumptions).  See also notes 1 and 7.
30. Delivery of benefit checks normally due January 3, 2016 occurred on December 31, 2015. Consequently, the SMI premiums withheld from the checks ($2,281 million, consisting of $2,097 million for Part B and $184 million for Part D) and the associated general revenue contributions ($5,446 million, all attributable to Part B) were added to the SMI trust fund on December 31, 2015. These amounts are excluded from the premium income and general revenue income for calendar year 2016 (refer to note 9).
31. 2017 includes an estimated $10,469 million for premiums paid directly to Part D plans (based on 2018 Trustees Report intermediate assumptions).  See also notes 1 and 7.
Note: Totals do not necessarily equal the sums of rounded components.
