Year	Number
1961	12.328621908127209
1962	19.12099644128114
1963	30.802513464991023
1964	44.929475587703436
1965	109.5290251916758
1966	165.04676324958737
1967	231.16979728473126
1968	375.9398496240602
1969	538.5509492444788
1970	535.0269438029254
1971	542.770731707317
1972	575.1235910618944
1973	680.518444666002
1974	1104.8613901165127
1975	1458.2204246713852
1976	1690.7132696606382
1977	1938.5053960496844
1978	2237.362188648428
1979	2244.571896763621
1980	3018.8756668034466
1981	2906.603579510389
1982	3145.0948062654575
1983	3271.3194301053063
1984	3412.531017369727
1985	3837.68115942029
1986	3804.771784232365
1987	3955.276277523889
1988	4129.40074906367
1989	4276.126878130217
1990	4492.89010067114
1991	4147.679324894515
1992	4249.045396690708
1993	4356.456776947705
1994	4420.600858369099
1995	4585.313174946004
1996	4611.038678835289
1997	4642.153644123441
1998	4674.751929437707
1999	4707.972462802576
2000	4532.127849798838
2001	4510.0900090009
2002	4482.674813306177
2003	4451.9081191721625
2004	4416.793788536196
2005	4382.394495412845