Sales of existing homes in the United States set a record in June with home prices advancing at the fastest pace in nearly 25 years.

The National Association of Realtors today reported that existing homes were sold at a seasonally adjusted annual rate of 7.33 million units last month, a gain of 2.7% from May.

The strong jump in sales helped to push the median price of an existing home up to a record of US$219,000 last month, a gain of 14.7% from the median, for prices a year ago. That was the biggest jump in prices since November 1980.

The performance in June beat expectations. Many economists had expected sales last month would be flat, given the strong increases in previous months.

“Just when you think sales activity is ready to settle into a more sustainable pace, the housing market continues to surprise,” said David Lereah, NAR’s chief economist, in a release.

Earlier this month U.S. Federal Reserve Chairman Alan Greenspan some parts of the U.s. could be in the grip of a “speculative fervor”.

The boom in housing is being driven by mortgage rates, which have remained near rock-bottom levels this year even as the Federal Reserve has continued to raise short-term interest rates.