The National Association of Realtors released existing homes sales figures in the U.S. on Monday. Sales of existing homes rose 5.1% to a seasonally adjusted annual rate of 5.35 million in May from 5.09 million in April. It was the highest level since November 2009.

April's figure was revised up from 5.04 million units.

Analysts had expected an increase to 5.26 million units.

The increase was driven by the return of first-time buyers onto the market.

The NAR chief economist Lawrence Yun said that "the return of first-time buyers in May is an encouraging sign and is the result of multiple factors, including strong job gains among young adults, less expensive mortgage insurance and lenders offering low downpayment programs".

He added that more first-time buyers are expected to enter the housing market in coming months.

"Overall supply still remains tight, homes are selling fast and price growth in many markets continues to teeter at or near double-digit appreciation," Yun also said.