The number of homes sold in Sun City and Sun City West soared last month compared to May 2011, a new study revealed this week.

The W.P. Carey School of Business at Arizona State University reported that 141 single-family homes were sold in Sun City West last month for a median sale price of $166,154. In Sun City, the 134 homes sold netted a median price of $110,683.

In May 2011, seven homes were sold in Sun City and one in Sun City West, the report showed.

Elsewhere in the West Valley, sales numbers also boomed.

Surprise saw a 916 percent increase in the number of homes sold from May to May, 38 to 386; Peoria, 61 to 453; Glendale, 79 to 532; El Mirage, 15 to 95; and Youngtown two to 13.

Valleywide home prices have been zooming up for months, and the streak continued in May, according to the Carey School report.

The median single-family home price jumped 32.4 percent from May 2011 to May 2012. It increased from $111,000 to $147,000. At the same time, the median townhouse/condo price rose 37.3 percent, from $69,900 to $96,000, and the average price per square foot shot up more than 22 percent. Prices have been increasing since they reached a low point in September 2011.

The report’s author, Mike Orr, said high demand and low supply remain the dominant factors in the Phoenix-area housing market.

For example, the number of active listings for single-family homes without a contract in the Valley was down to 8,550 as of June 1. Fierce competition for available homes has continued to push prices up, Orr said.

“Most houses below $250,000 priced realistically are attracting large numbers of offers in a short time, and many exceed the asking price,” said Orr, director of the Center for Real Estate Theory and Practice at the W. P. Carey School of Business. “We recently saw a Chandler home get 84 offers and a Glendale home receive 95. The Glendale house closed within four weeks for 17 percent above asking price. Needless to say, this is not something we would see in a normal market.”

“Prices gained further strength over the last month, but I suspect they cannot continue to rise at the extremely fast rate we experienced this spring,” Orr said. “This rate can’t be sustained long term, and the most likely time for prices to stabilize is during the hot summer months of June through September.”