International Center for Disability Information 

By Age Group, The Number Of People Receiving Federally Administered Supplemental Security Income (SSI) Payments, By Source Of Payment (2000). 
Age Group  Total  Federal Payment Only  Federal And State Supplementation  State Supplementation Only 

All Ages 
6, 601,686 
4,121,049 
2,198,858 
281,779 
Under 18  846,784 
607,415 
237,064 
2,305 
1864  3,744,022 
2,413,695 
1,195,468 
134,859 
65 Years And Over  2,010,880 
1,099,939 
766,326 
144,615 
Note: To calculate the percent
of people out of the total number of people who receive Federally
administered SSI through a particular source who are in a certain age group,
divide the number of people who receive Federally administered
SSI through a particular source who are in a certain
age group by the total number of people who receive Federally
administered SSI who are in the same age group and multiply the result
by 100. Example: Calculate the percent out of the total number of people who
are under 18 who receive SSI through Federal payment only. This calculation
would be: 607,415/846,784=.717 and .717x100= 71.7%
Source: Social Security Administration, SSI Annual Statistical
Report, 2000.