Year	Number
1960	13255
1961	13382
1962	13517
1963	13641
1964	13741
1965	13815
1966	13865
1967	13896
1968	13925
1969	13969
1970	14186
1971	14634
1972	15150
1973	15674
1974	16200
1975	16711
1976	17191
1977	17645
1978	18070
1979	18480
1980	18883
1981	19283
1982	19662
1983	19994
1984	20267
1985	20465
1986	20584
1987	20636
1988	20622
1989	20505
1990	20260
1991	20119
1992	20222
1993	20382
1994	20527
1995	20656
1996	20760
1997	20846
1998	20914
1999	20954
2000	20964
2001	21064
2002	21311
2003	21591
2004	21853
2005	22108
2006	22353
2007	22594
2008	22823
2009	23015
2010	23160
2011	23327
2012	23568
2013	23722
2014	24093
2015	24500
2016	24685
2017	24917
2018	25129
2019	25384
2020	25619
2021	25766
2022	25850
2023	25896