Hidden in pages of economic data prepared by the Council of Economic Advisors for Congress is the sad truth behind the declining American middle class – proof that although hourly wages and weekly earnings seem to be rising, buying power in "real" dollars is not. The data explains the main reason working families are no better off in 1999 than they were in 1989 – even though they are making more money.

The data, prepared for the Joint Economic Committee of the 106th Congress and released in August, shows that average hourly and weekly wage scales rise steadily over the 11 years covered by the report. However, when the raises are converted into 1982 dollars to approximate today's buying power, they turn out to be an accounting mirage.

For example, average gross hourly earnings in 1989 for workers in private nonagricultural industries was $9.66 per hour, according to the CEA report. By July 1999, this average had increased to $13.29 – an average raise of $3.63. But the rub is that spending power in "real" 1982 dollars increased only from $7.64 in 1989 to $7.88 in June 1999. Conversion to the baseline of 1982 dollars is a better gauge of consumer buying power from year to year, according to accepted economic practice.

Deceptively enough, the percentage gain of wage rates climbed slowly over the 11 years, averaging about 3 percent over the period of the report. Yet the percent change in 1982 dollars often went into negative territory in the early 1990s, showing that despite a raise in current dollars, workers were in reality losing buying power.

The CEA report also documents the growth of average weekly hours of overtime in manufacturing from a base work week of 41.0 hours and 3.8 hours of overtime in 1989 to a base work week of 41.9 hours plus 4.8 hours of overtime in July 1999.