An advocacy group for older Americans says drug makers have boosted the wholesale price of many brand-name prescription drugs widely used by seniors.

The AARP reports the prices charged by manufacturers climbed 6.6 percent for a sample of 195 drugs. That's down from the seven-point-one percent increase in the year that ended December 31st, but still well ahead of the three percent general inflation rate.

Looking at the first three months of this year, the study found the biggest price increase, 6.1 percent was for insulin, sensitizing drugs for diabetics.

The Pharmaceutical Research and Manufacturers of America accused AARP of using "fuzzy math."