* Gas-directed rig count plumbs new 18-year low * Horizontal rigs slip for fifth time in six weeks * Oil rig count retreats from nine-month high NEW YORK, June 21 (Reuters) - The number of rigs drilling for natural gas in the United States fell by four this week to an 18-year low of 349, data from Houston-based Baker Hughes showed on Friday. The gas-directed rig count, which has dropped for four straight weeks, is at its lowest since June 1995. The count is just below the previous low of 350 hit on May 10. Producers have mostly been curbing dry-gas drilling in favor of more profitable oil and liquids-rich plays such as Eagle Ford in Texas and Marcellus in Appalachia. Gas prices hit a 21-month high of $4.444 per million British thermal units in early May and stirred concerns that producer hedging at higher prices could keep dry gas output flowing. But gas futures prices on Friday, which showed little reaction to the rig report, were trading down 8 cents to about $3.80, just above the three-month low of $3.71 hit last week. The oil-focused rig count fell by eight this week to 1,405 after posting a nine-month high of 1,413 the previous week, Baker Hughes data showed. The oil count is down 16 rigs from the same week last year. Baker Hughes reported horizontal rigs, the type often used to extract oil or gas from shale, lost ground for the fifth time in six weeks, shedding seven to 1,079. The horizontal count is down nearly 10 percent from the record high of 1,193 set in May 2012. Drilling for natural gas has mostly been in decline for the last 20 months. The count is down about 63 percent since peaking in October 2011 at 936, but so far production has not slowed much, if at all, from the record high hit last year. The associated gas produced from shale oil and shale gas liquids wells has kept dry gas flowing at a brisk rate. The U.S. Energy Information Administration still expects gas output in 2013 to post a record high for a third year.