Contributions to the Social Security and Medicare Trust Funds, by program and source, 2006-2015
(in millions of dollars)

Program and source 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Social Security Trust Funds
Old-Age and Survivors Insurance a $550,415 $578,069 $590,122 $590,322 $569,018 $592,314 $628,302 $645,678 $674,584 $710,334
Employer 253,705 265,753 272,060 269,586 257,245 271,395 285,328 294,995 305,279 322,395
Employee 251,813 263,856 269,956 267,440 257,893 184,227 191,028 292,241 302,850 319,939
Self-employed 29,269 31,269 32,540 33,366 29,635 26,728 27,538 33,578 38,104 37,169
General Fund Reimbursement b b b b 2,155 87,753 97,735 4,169 395 278
Taxation of benefits 15,628 17,192 15,566 19,930 22,090 22,211 26,675 20,694 27,957 30,554
Disability Insurance a 92,038 96,636 98,879 98,820 94,728 98,389 102,744 106,523 111,488 116,508
Employer 43,081 45,127 46,199 45,783 43,684 46,086 48,451 50,095 51,840 54,747
Employee 42,760 44,804 45,841 45,418 43,794 31,259 32,487 49,603 51,427 54,330
Self-employed 4,967 5,312 5,526 5,664 5,034 4,537 4,677 5,704 6,470 6,312
General Fund Reimbursement b b b b 366 14,927 16,546 729 71 47
Taxation of benefits 1,230 1,393 1,313 1,955 1,852 1,581 583 391 1,680 1,071
Medicare Trust Funds
Hospital Insurance a 194,238 205,289 213,364 206,173 199,102 214,003 227,814 238,544 248,762 264,489
Employer 84,417 89,093 91,981 88,242 84,397 91,381 95,618 102,318 104,720 112,027
Employee 84,417 89,093 91,981 88,242 84,397 91,381 95,618 102,318 104,720 112,027
Self-employed 12,439 13,669 14,732 14,405 13,238 12,830 14,494 16,182 18,006 17,020
Voluntarily enrolledc 2,645 2,841 2,938 2,908 3,310 3,267 3,441 3,417 3,251 3,206
Taxation of benefits 10,319 10,593 11,733 12,376 13,760 15,143 18,643 14,310 18,066 20,208
Supplementary Medical Insurancea, d 42,853 46,773 50,232 56,040 51,986 57,514 58,024 63,085 65,644 69,446
Aged 36,346 39,676 42,335 47,433 43,168 47,646 48,495 52,814 55,164 58,593
Disabled 6,507 7,096 7,897 8,606 8,818 9,868 9,529 10,270 10,479 10,852
a Totals do not necessarily equal the sum of rounded components. Employment taxes depend on tax rates, and, for the Old-Age and Survivors Insurance and Disability Insurance Trust Funds, wage bases (taxable maximums). (Beginning in 1994, no wage base applies to Medicare's Hospital Insurance program.) Employer and employee contributions differ by estimated amounts of employee tax overpayments and by employee tax on tips.
b Between -$500,000 and $500,000.
c Beginning in July 1973, aged ineligibles may voluntarily enroll for Hospital Insurance.
d Includes premiums paid on behalf of eligibles by State governments under "buy-in" arrangements.