Year	Number
1960	6845
1961	6845
1962	6845
1963	6845
1964	6845
1965	13991
1966	13991
1967	13991
1968	13991
1969	13991
1970	173000
1971	173000
1972	173000
1973	173000
1974	173000
1975	21660
1976	22500
1977	23800
1978	24700
1979	26000
1980	27300
1981	29000
1982	30000
1983	31000
1984	32000
1985	33275
1986	35000
1987	36000
1988	37000
1989	38550
1990	40000
1991	41500
1992	44848
1993	43000
1994	41500
1995	42150
1996	63850
1997	86800
1998	115675
1999	140392
2000	152687
2001	197496
2002	220000
2003	255000
2004	274557
2005	278973
2006	256000
2007	300000
2008	343591
2009	363000
2010	333066
2011	338844
2012	312000
2013	281200
2014	235734
2015	226718
2016	248640
2017	246720
2018	248631
2019	242859
2020	223469
2021	197690
2022	177152