NEW YORK - The number of rigs drilling for natural gas in the United States fell by five this week to 721, according to a report on Friday by oil services firm Baker Hughes in Houston.

The U.S. natural gas drilling rig count has risen in 11 of the past 13 weeks but is still 816 rigs below the 1,537 rigs drilling in same week last year.

The number of rigs peaked above 1,600 in September 2008. During the week ended July 17, 2009, the natural gas rig count slipped to 665, its lowest level since May 3, 2002, when there were 640 gas rigs operating.

Tighter access to credit and a 70 percent slide in natural gas prices over the past 15 months to below $4 per mmBtu forced many producers to scale back gas drilling operations.

The steep declines in drilling this year have started to slow production and tighten supplies, but most traders agreed it has not been enough yet to offset record high inventories and steep recession-related cuts in demand, particularly from the industrial sector. (Reporting by Edward McAllister; Editing by Walter Bagley)