U.S. home builder sentiment rose in May, maintaining the high level of confidence that builders have held for more than 16 months, the National Association of Home Builders (search) reported Monday.

The NAHB said its housing market index registered a seasonally adjusted 70 in May from a reading of 67 in April.

A reading above 50 indicates more than half of builders surveyed view sales conditions as favorable rather than poor.

Robust buyer demand for new single-family homes (search), brought on by continued low mortgage rates (search) and an improving job market, nudged builder confidence up three points in May, close to the high side of the strong 67-71 confidence range that builders have held for more than a year.

"Builders have seen an uptick in traffic and sales brought on by improving economic conditions and mortgage rates that continue to remain at affordable levels. They have confidence in the overall housing market and expect sales to stay strong for the next six months," said NAHB President Dave Wilson, a custom home builder from Ketchum, Idaho.

The NAHB's index of buyer traffic was at a seasonally adjusted 53 in May up from 50 in April. The current sale index registered 76 in May versus 73 in the prior month.

Meanwhile, the index of builder expectations for the next six months was at 77 in May versus 76 in April, NAHB said.