Shoppers bought 1.72 million new cars in October, flooding the market with their trade-ins -- 966,464 used cars that month, according to the National Automobile Dealers

Association (NADA), which publishes a monthly guide on used-car values.

Typically, the number of trade-ins each month is between about 656,000 and 900,000. June 2001 was the closest to October with 908,000.

While dealers say used-car sales are steady, they haven't put a big dent into the growing

supply, according to Paul Taylor, NADA's chief economist. "With the economy slowing, the ability to absorb the used cars has decreased, exactly at the time when the surge of used cars is coming because of the zero percent financing," Taylor told the Grand Rapids Press.

One of the reasons used-car prices are soft is because the zero percent financing has converted some buyers of late-model used

cars into new-car buyers, according to Taylor.

Making a deal on a used vehicle is tricky for both consumers and dealers because the vehicle is always declining in value. The rate of decline varies depending on economic conditions and supply and demand for vehicles.

Data through August from NADA shows the annual depreciation rate rose to about 15 percent in 2001 from 13 percent in 2000. The increase is

partly due to strong sales of new vehicles in 1999 and 2000, some of which are now starting to show up in the used market.