Contributions to the Social Security and Medicare Trust Funds, by program and source, 2009-2018
(in millions of dollars)

Contributions to the Social Security and Medicare Trust Funds,
by program and source, 2009-2018
(in millions of dollars)
Program and source 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Social Security Trust Funds
Old-Age and Survivors Insurance a $590,322 $569,018 $592,314 $628,302 $645,678 $674,584 $710,334 $710,497 $742,399 $750,371
Employer 269,586 257,245 271,395 285,328 294,995 305,279 322,395 322,652 336,293 340,901
Employee 267,440 257,893 184,227 191,028 292,241 302,850 319,939 319,940 333,542 338,475
Self-employed 33,366 29,635 26,728 27,538 33,578 38,104 37,169 36,195 36,670 36,489
General Fund Reimbursement b 2,155 87,753 97,735 4,169 395 278 87 17 18
Taxation of benefits 19,930 22,090 22,211 26,675 20,694 27,957 30,554 31,623 35,877 34,488
Disability Insurance a 98,820 94,728 98,389 102,744 106,523 111,488 116,508 158,600 169,063 169,719
Employer 45,783 43,684 46,086 48,451 50,095 51,840 54,747 75,347 79,498 80,576
Employee 45,418 43,794 31,259 32,487 49,603 51,427 54,330 74,887 78,854 79,992
Self-employed 5,664 5,034 4,537 4,677 5,704 6,470 6,312 7,157 8,734 8,617
General Fund Reimbursement b 366 14,927 16,546 729 71 47 15 3 3
Taxation of benefits 1,955 1,852 1,581 583 391 1,680 1,071 1,194 1,973 530
Medicare Trust Funds
Hospital Insurance a 206,173 199,102 214,003 227,814 238,544 248,762 264,489 279,821 289,164 296,082
Employer 88,242 84,397 91,381 95,618 102,318 104,720 112,027 118,309 121,488 125,025
Employee 88,242 84,397 91,381 95,618 102,318 104,720 112,027 118,309 121,488 125,025
Self-employed 14,405 13,238 12,830 14,494 16,182 18,006 17,020 16,899 18,520 18,232
Voluntarily enrolledc 2,908 3,310 3,267 3,441 3,417 3,251 3,206 3,282 3,463 3,608
Taxation of benefits 12,376 13,760 15,143 18,643 14,310 18,066 20,208 23,022 24,206 24,192
Supplementary Medical Insurancea, d 56,040 51,986 57,514 58,024 63,085 65,644 69,446 72,055 81,522 93,312
Aged 47,433 43,168 47,646 48,495 52,814 55,164 58,593 60,618 69,009 80,041
Disabled 8,606 8,818 9,868 9,529 10,270 10,479 10,852 11,438 12,513 13,271
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.