If money income stays the same, but the price of one good goes up, the effective purchasing power falls, and vice versa.
Purchasing power is linked with Inflation.
... out with 22.3% under the age of 18, 8.0% from 18 to 24, 31.0% from 25 to 44, 21.9% from 45 to 64, and 16.9% who are 65 years of age or older. The median age is 39 years. ...