Year	Number of
1956	4181
1957	4165
1958	4152
1959	4139
1960	4155
1961	4202
1962	4275
1963	4335
1964	4389
1965	4385
1966	4346
1967	4301
1968	4244
1969	4168
1970	4046
1971	3895
1972	3716
1973	3544
1974	3423
1975	3335
1976	3304
1977	3289
1978	3271
1979	3250
1980	3213
1981	3172
1982	3142
1983	3143
1984	3170
1985	3179
1986	3194
1987	3204
1988	3195
1989	3154
1990	3123
1991	3064
1992	3014
1993	2949
1994	2898
1995	2835
1996	2808
1997	2784
1998	2737
1999	2701
2000	2595
2001	2473
2002	2331
2003	2201
2004	2077
2005	1998
2006	1954
2007	1935
2008	1925
2009	1917
2010	1871
2011	1807
2012	1725
2013	1635
2014	1552
2015	1471