The Bay Area’s housing market had its strongest April sales in six years, and the median price rose on a year-over-year basis for the first time in 19 months.

Buyers in the nine-county region last month purchased 7,675 single-family houses and condominiums, according to DataQuick, a San Diego real estate information service. Sales were up 13 percent from a year earlier.

The median price rose to $390,000, up almost 9 percent from March and an increase of 8 percent from April 2011. The last time the region saw a year-over-year jump in the median price was September 2010, when the $395,000 median was up 8 percent from the prior year.

Analysts suggest that fence-sitters are moving to take advantage of lower prices and historically low mortgage rates.

“It appears that the market is taking a step in the direction of normalization, but only a step,” said John Walsh, DataQuick president.

The rise in the median price was expected from the change in the type of homes sold, Walsh said.

Foreclosure resales – homes that had been foreclosed on in the prior 12 months – fell to nearly 22 percent of all resales in April, the lowest level since January 2008. Foreclosures amounted to nearly 26 percent of March sales and 28 percent in April 2011.

Meanwhile, a greater portion of homes sold last month in what is commonly called the market’s move-up segment. Homes selling for $500,000 or more climbed to nearly 38 percent of all sales last month, up from 33 percent in March and from 36 percent a year earlier.

— Robert Digitale