Home prices in Los Angeles County continued their skyward ascent in December, but the pace of sales slowed over the year-prior period, according to research firm DataQuick Information Systems.

The median price of new and used homes sold in L.A. County during December rose to $418,000, a 21.2 percent increase from $345,000 in December 2003. Prices rose by $2,000 in December from November.

However, the number of homes sold fell by 7.4 percent from the year-ago period, to 10,242 from 11,059 in December 2003.

In Southern California as a whole, the number of homes sold in December fell 6.5 percent from the year-ago period to 30,317 homes. It was the third-strongest December in terms of number of homes sold since 1988, DataQuick said

The median price of $424,000 was 22.5 percent higher than the $346,000 price logged in December 2003. In every month of 2004, Southern California home prices logged year-over-year increases of more than 20 percent, DataQuick said.

Orange County had the highest-priced homes in Southern California at $551,000, followed by Ventura County ($522,000), San Diego ($491,000), Los Angeles, Riverside ($371,000) and San Bernardino ($281,000).