data methane; input sample depth gas; cards; 1 175 2.5 2 252 5.7 3 318 8.7 4 356 10.8 5 516 11.8 6 553 13.1 7 571 11.8 8 561 11.5 9 556 10.9 10 823 15.5 11 892 16.8 12 1439 17.1 13 1440 16.7 14 489 10.9 15 1296 17.5 ; run;