SAN FRANCISCO (Reuters) - Sales of houses and condominiums in the most populous Southern California counties fell 29.9 percent from the previous month and 48.5 percent from a year earlier, DataQuick Information Systems said on Tuesday.

The report covers the counties of Los Angeles, Orange, San Diego, Riverside, San Bernardino and Ventura and showed a total of 12,455 new and existing homes and condos sold in September, the lowest since the company began recording the data in 1988.