Year	Number
1960	1648
1961	1648
1962	1648
1963	1648
1964	1648
1965	2600
1966	2600
1967	2600
1968	2600
1969	2600
1970	2854
1971	2854
1972	2854
1973	2854
1974	2854
1975	3567
1976	3771
1977	3969
1978	3992
1979	4188
1980	4920
1981	5384
1982	5830
1983	6488
1984	7071
1985	7243
1986	7346
1987	8522
1988	8772
1989	9667
1990	11169
1991	12464
1992	12837
1993	13812
1994	15203
1995	17164
1996	21294
1997	24195
1998	27063
1999	33778
2000	39223
2001	51071
2002	56603
2003	60925
2004	65834
2005	75904
2006	82521
2007	80005
2008	81076
2009	84796
2010	114546
2011	104696
2012	111979
2013	126362
2014	154417
2015	169006
2016	200812
2017	214893
2018	228097
2019	242241
2020	281638
2021	301055
2022	306900