If you feel like your Social Security check doesn't stretch as far as it once did, there's a likely explanation for it. Since 2000, the buying power of monthly benefits has fallen by more than a third, according to an annual report released Thursday by the Senior Citizens League, an advocacy group based in Alexandria, Virginia. In other words, the cost of goods and services common among retirees have collectively risen faster than the cost-of-living adjustment, or COLA, that Social Security recipients get every year. "People who recently retired might have seen only a [small] decrease in buying power," said Mary Johnson, a policy analyst for the league. "But those retired for a long time are feeling the cumulative effect of this."

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About 47 million older Americans receive Social Security. Overall, the benefits comprise about a third of income among those age 65 or older, according to the Social Security Administration. The league's annual report examines the costs that typically comprise household budgets of older Americans and compares their price change with annual COLAs. Based on those comparisons, the research found a 4 percent loss in Social Security buying power from January 2017 to January 2018 and a 34 percent decrease since 2000. While COLA increases since 2000 cumulatively have equaled 46 percent — matching inflation over those years — typical retiree expenses grew by 96.3 percent, the study shows. Of the 39 costs analyzed in the report, 26 grew faster than the percentage increase in COLAs from 2000 to 2018.

Top six fastest-growing retiree costs Item Cost in 2000 Cost in 2018 Increase Medicare Part B monthly premium $45.50 $134 195% Prescription drugs annual out-of-pocket $1,102 $3,172.72 188% Home heating oil (gallon) $1.15 $3.22 181% Medigap $119 $306.64 158% Propane gas (gallon) $1.01 $2.60 157% Real estate taxes $690 $1,579.06 129%