Year	Number
1970	39238
1971	40468
1972	39942
1973	38524
1974	38867
1975	37681
1976	37914
1977	37908
1978	38867
1979	39064
1980	37741
1981	35048
1982	36157
1983	38453
1984	39051
1985	38078
1986	41197
1987	42077
1988	44481
1989	47176
1990	45388
1991	46808
1992	47110
1993	51484
1994	52232
1995	51789
1996	58214
2009	54687
2010	43671
2011	41699
2012	44254
2013	51754
2014	50405
2015	53082