ID	Year	Yield
1	1957	48.3
2	1958	52.8
3	1959	53.1
4	1960	54.7
5	1961	62.4
6	1962	64.7
7	1963	67.9
8	1964	62.9
9	1965	74.1
10	1966	73.1
11	1967	80.1
12	1968	79.5
13	1969	85.9
14	1970	72.4
15	1971	88.1
16	1972	97
17	1973	91.3
18	1974	71.9
19	1975	86.4
20	1976	88
21	1977	90.8
22	1978	101
23	1979	109.5
24	1980	91
25	1981	108.9
26	1982	113.2
27	1983	81.1
28	1984	106.7
29	1985	118
30	1986	119.4
31	1987	119.8
32	1988	84.6
33	1989	116.3
34	1990	118.5
35	1991	108.6
36	1992	131.5
37	1993	100.7
38	1994	138.6
39	1995	113.5
40	1996	127.1
