i	x	y
1	10	12.6
2	10	11.0
3	10	12.1
4	10	10.9
1	20	15.3
2	20	16.1
3	20	14.9
4	20	15.6
1	30	17.9
2	30	18.3
3	30	18.6
4	30	17.8
1	40	19.2
2	40	19.6
3	40	18.9
4	40	20.0