15   21.5
15   21.9
15   21.7
15   21.6
15   21.7
15   21.5
15   21.8
20   21.7 
20   21.4
20   21.5
20   21.5
30   21.9
30   21.7
30   21.8
30   21.7
30   21.6
30   21.8