Year	Number
1970	29500
1971	29400
1972	32100
1973	35200
1974	30800
1975	36900
1976	38200
1977	41000
1978	41500
1979	42700
1980	42700
1981	34100
1982	16400
1983	25800
1984	28800
1985	28400
1986	30700
1987	30200
1988	28900
1989	31500
1990	28600
1991	19600
1992	22400
1993	27600
1994	30500
1995	32100
1996	35900
1997	38300
1998	38400
1999	43800
2000	52371
2001	71799
2002	69842
2003	73137
2004	77690
2005	78992
2006	83451
2007	89289
2008	90031
2009	83053
2010	82630
2011	82052
2012	81194
2013	83336
2014	77094
2015	68326
2016	84075
2017	106424
2018	123903
2019	131419
2020	48381
2021	60781