Year	Number
1960	19932
1961	19932
1962	19932
1963	19932
1964	19932
1965	26300
1966	26300
1967	26300
1968	26300
1969	26300
1970	35000
1971	35000
1972	35000
1973	35000
1974	35000
1975	49700
1976	50900
1977	53500
1978	53500
1979	52945
1980	52586
1981	56204
1982	60493
1983	64213
1984	66901
1985	76678
1986	81322
1987	81713
1988	85179
1989	89091
1990	105285
1991	131566
1992	167251
1993	208480
1994	250531
1995	290262
1996	357262
1997	415610
1998	462824
1999	487325
2000	493523
2001	511302
2002	434772
2003	458675
2004	423000
2005	319000
2006	342692
2007	369656
2008	316591
2009	302451
2010	263055
2011	270068
2012	253143
2013	250340
2014	254500
2015	252849
2016	310213
2017	297027
2018	363820
2019	398048
2020	436249
2021	473617
2022	446831