According to Kasriel's calculation, last year Americans spent approximately $472 billion more than they earned after taxes -- a negative savings rate of 5.2 percent. That spending is double the previous year -- and a record high.

Going back to 1929, Kasriel found just a dozen years in which households spent more than they earned by his calculation. Two were during the Great Depression. Three were in the decade following World War II, when consumers unleashed pent-up savings accumulated during the war (when there was little available to consume). The other seven years of negative savings have occurred since 1999.

Whichever reality you believe, it's clear that Americans are highly leveraged. The ratio of debt to assets hit a near record 18.2 percent in the third quarter of 2005, the most recent data available from the Federal Reserve's Flow of Funds Database. This ratio, tracked since 1952, measures the amount of debt Americans have, relative to the market value of all their assets -- savings accounts, stocks, bonds, real estate, etc. In the early 1980s, the ratio was around 13 percent; in the early 1950s, 7 percent.

Meanwhile, the debt service ratio -- the percentage of after-tax household income that goes to cover required principal and interest payments on debt -- hit a record high of 13.75% in the third quarter of 2005, the most recent data available.