Sales for previously owned homes fell in October to the lowest levels since the National Association of Realtors started tracking the number 1999.

The NAR said today sales dropped to an annual rate of 4.97 million despite a drop in median home prices of 5 percent, also the biggest decline on record, compared with October 2006 prices.

The number of homes for sale at the end of the month rose 1.9 percent to 4.45 million. At the current sales pace, that represented 10.8 months’ supply, compared with 10.4 months in September.

Meanwhile, the inventory of single-family homes represented a 10.5 months’ supply, the highest since July 1985. Resales of single- family homes were unchanged at an annual rate of 4.37 million. Sales of condos and co-ops fell 9.1 percent to a 600,000 rate.