Year	Number
1970	23.30952
1971	23.69048
1972	20.98462
1973	18.26027
1974	19.90541
1975	19.90526
1976	17.62805
1977	16.96818
1980	12.11382
1981	11.55814
1982	14.84326
1984	17.20433
1985	19.47308
1986	11.96146
2003	7.22769