Notes
1. 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. Includes, net of transfers from States, all government transfers required to fund benefit payments, administrative expenses, and State expenses for making low-income eligibility determinations.
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. 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.
5. 2006 includes an estimated $2,299 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
6. 2007 includes an estimated $2,405 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
7. 2008 includes an estimated $3,157 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
8. 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, 2010 occurred on December 31, 2009 and delivery of benefit checks normally due January 3, 2016 occurred on December 31, 2015. Consequently, the Part D premiums withheld from these benefits were added to the Part D account on December 31, 2009 (about $209 million) and December 31, 2015 (about $184 million).  These premiums are excluded from the premium income for calendar year 2010 and 2016. 
9. 2009 includes an estimated $3,851 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
10. 2010 includes an estimated $4,378 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
11. 2011 includes an estimated $4,990 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
12. 2012 includes an estimated $5,215 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
13. 2013 includes an estimated $6,720 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
14. 2014 includes an estimated $7,769 million for premiums paid directly to Part D plans (based on 2015 Trustees Report intermediate assumptions).  See also notes 1 and 4.
15. 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 4.
16. 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 4.
17. 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 4.
Note: Totals do not necessarily equal the sums of rounded components.

