x (cm)	s(x) (cm)
45	16.1
40	15.2
35	14.3
30	13.4
27.5	12.9
0	8.0
-5	7.1
-10	6.2
-15	5.2
-20	4.3
-25	3.3
-30	2.4
-35	1.5
-40	0.7