BEND, Ore. (CNN/Money) - Existing home sales remain near record levels, but prices in individual metro markets were a mixed bag during the first quarter of 2004. While strong markets saw huge price gains, weaker markets experienced sharper declines than seen in recent quarters.

Of the 126 markets tracked by the National Association of Realtors (NAR), 35 had double-digit price increases over the past year. Prices in Riverside and San Bernardino counties near Los Angeles increased 32.9 percent to $258,900 between the first quarters of 2003 and 2004; prices in Las Vegas were up 31.3 percent to $224,900.

The top 5 These markets showed the biggest gains in median home prices in the first quarter. Metro area  Median price  Q1 gain  Riverside/San Bernadino, CA  $258,900  32.9%  Las Vegas, NV  $224,900  31.3%  Orange County, CA  $572,500  28.1%  Los Angeles area, CA  $387,700  25.8%  Sarasota, FL  $239,900  24.5%   Source:  National Association of REALTORS

"It's a simple matter of supply and demand," said David Lereah, NAR's chief economist in a release. "We continue to have more home buyers than sellers in most of the country, which results in tight housing inventories and higher rates of home price appreciation."

Low interest rates certainly helped. During the first quarter, the 30-year fixed rate mortgage averaged 5.6 percent, according to Freddie Mac, making it the second lowest quarter ever.

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Nationally, the median existing-home price was $170,800, up 6.5 percent from the first quarter of 2003 but down slightly from the previous quarter when it was $171,600.

Among the 16 metro markets with price decreases, however, the losses were greater than in recent quarters. Median prices in Springfield, Ill. decreased 10.2 percent to $84,000 over the past year. In Charleston, WV prices sunk 9.8 percent to $99,600.

NAR's Lereah attributed the declines to weak local economies rather than a housing market bubble.

"Generally, these areas are now recovering jobs and should gradually turnaround," he said. "In other words, these are not harbingers of local price bubbles because those are home prices were never inflated to begin with."