Year	Number
1960	2932
1961	2924
1962	2909
1963	2890
1964	2875
1965	2859
1966	2841
1967	2827
1968	2810
1969	2788
1970	2770
1971	2786
1972	2837
1973	2896
1974	2958
1975	3028
1976	3104
1977	3178
1978	3254
1979	3326
1980	3399
1981	3393
1982	3389
1983	3374
1984	3347
1985	3310
1986	3261
1987	3204
1988	3138
1989	3063
1990	3004
1991	3016
1992	3033
1993	3041
1994	3041
1995	3031
1996	3014
1997	2991
1998	2963
1999	2931
2000	2896
2001	2866
2002	2882
2003	2911
2004	2930
2005	2941
2006	2945
2007	2943
2008	2936
2009	2924
2010	2905
2011	2876
2012	2858
2013	2861
2014	2851
2015	2852
2016	2862
2017	2862
2018	2863
2019	2861
2020	2831
2021	2782
2022	2721
2023	2650