Year	Number
1960	42801
1961	41967
1962	40724
1963	38945
1964	36328
1965	33013
1966	29688
1967	26851
1968	24717
1969	23309
1970	22527
1971	22049
1972	21586
1973	20814
1974	19409
1975	17411
1976	15193
1977	13048
1978	11205
1979	9794
1980	8776
1981	7960
1982	7221
1983	6617
1984	6263
1985	6158
1986	6172
1987	6179
1988	6103
1989	5909
1990	5591
1991	5199
1992	4750
1993	4323
1994	3977
1995	3680
1996	3449
1997	3283
1998	3133
1999	2948
2000	2721
2001	2523
2002	2385
2003	2270
2004	2168
2005	2098
2006	2066
2007	2075
2008	2105
2009	2122
2010	2106
2011	2068
2012	2022
2013	1979
2014	1942
2015	1891
2016	1817
2017	1724
2018	1651
2019	1599
2020	1548
2021	1495
2022	1441