Year	Number
1961	22.972999286270404
1962	25.009848129008073
1963	27.389755245306514
1964	29.673377292919135
1965	32.678795607792885
1966	35.9941711974166
1967	39.002531899678566
1968	42.848005119708915
1969	46.679487828637065
1970	47.13542247636505
1971	51.15869741190331
1972	56.08483787817108
1973	61.24347696083087
1974	66.32212739357902
1975	76.38015229392022
1976	81.61474047972185
1977	87.60615425975658
1978	96.47237250104125
1979	106.72783059728448
1980	115.11111327937
1981	121.07135074617096
1982	122.75912047637549
1983	123.9450905076348
1992	125.67309821822589
1993	126.13600065320928
1994	129.86848101034502
1995	129.07358666196296
1996	127.52761850648798
1997	125.98341514968976
1998	127.35977539658809
1999	129.26659117742733
2000	137.81775902699385
2002	170.54936651635117