Year	Number
1960	4142
1961	4151
1962	4159
1963	4167
1964	4156
1965	4132
1966	4105
1967	4062
1968	3994
1969	3898
1970	3769
1971	3616
1972	3447
1973	3270
1974	3099
1975	2956
1976	2838
1977	2742
1978	2665
1979	2605
1980	2554
1981	2509
1982	2461
1983	2409
1984	2348
1985	2275
1986	2207
1987	2147
1988	2089
1989	2040
1990	1997
1991	1947
1992	1907
1993	1888
1994	1876
1995	1870
1996	1865
1997	1859
1998	1846
1999	1824
2000	1791
2001	1749
2002	1702
2003	1656
2004	1620
2005	1582
2006	1534
2007	1493
2008	1462
2009	1432
2010	1403
2011	1389
2012	1385
2013	1376
2014	1366
2015	1362
2016	1355
2017	1336
2018	1295
2019	1229
2020	1156
2021	1086
2022	1018