Contributions to the Social Security and Medicare Trust Funds, by program and source, 2004-2013
(in millions of dollars)

Contributions to the Social Security and Medicare Trust Funds,
by program and source, 2004-2013
(in millions of dollars)
Program and source 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
Social Security Trust Funds
Old-Age and Survivors Insurance a $486,726 $520,706 $550,415 $578,069 $590,122 $590,322 $569,018 $592,314 $628,302 $645,678
Employer 223,311 241,018 253,705 265,753 272,060 269,586 257,245 271,395 285,328 294,995
Employee 222,118 239,163 251,813 263,856 269,956 267,440 257,893 184,227 191,028 292,241
Self-employed 26,703 26,682 29,269 31,269 32,540 33,366 29,635 26,728 27,538 33,578
General Fund Reimbursement b b b b b b 2,155 87,753 97,735 4,169
Taxation of benefits 14,593 13,843 15,628 17,192 15,566 19,930 22,090 22,211 26,675 20,694
Disability Insurance a 81,287 87,150 92,038 96,636 98,879 98,820 94,728 98,389 102,744 106,523
Employer 37,922 40,929 43,081 45,127 46,199 45,783 43,684 46,086 48,451 50,095
Employee 37,720 40,614 42,760 44,804 45,841 45,418 43,794 31,259 32,487 49,603
Self-employed 4,534 4,534 4,967 5,312 5,526 5,664 5,034 4,537 4,677 5,704
General Fund Reimbursement b b b b b b 366 14,927 16,546 729
Taxation of benefits 1,111 1,073 1,230 1,393 1,313 1,955 1,852 1,581 583 391
Medicare Trust Funds
Hospital Insurance a 166,977 182,565 194,238 205,289 213,364 206,173 199,102 214,003 227,814 238,544
Employer 72,760 80,159 84,417 89,093 91,981 88,242 84,397 91,381 95,618 102,318
Employee 72,760 80,159 84,417 89,093 91,981 88,242 84,397 91,381 95,618 102,318
Self-employed 10,964 11,065 12,439 13,669 14,732 14,405 13,238 12,830 14,494 16,182
Voluntarily enrolledc 1,915 2,416 2,645 2,841 2,938 2,908 3,310 3,267 3,441 3,417
Taxation of benefits 8,577 8,765 10,319 10,593 11,733 12,376 13,760 15,143 18,643 14,310
Supplementary Medical Insurancea, d 31,435 37,535 42,853 46,773 50,232 56,040 51,986 57,514 58,024 63,085
Aged 26,737 31,722 36,346 39,676 42,335 47,433 43,168 47,646 48,495 52,814
Disabled 4,699 5,813 6,507 7,096 7,897 8,606 8,818 9,868 9,529 10,270
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.