What is the percentage loss of distance of a golf ball at sea level?

I know a golf ball will lose distance at sea level versus an inland course. Is there a percentage loss at sea level versus lets say a golf ball hit at a course that is 1000 ft above sea level. Is that 2% 4% 6%? Anyone know the percentage loss?|||i dont know the actual percentage but i think its quite a bit. i used to work at pebble beach and played all those courses which say they are 6800 yards but it plays much more longer.