Year	Number
1970	71700
1971	75600
1972	79000
1973	71100
1974	79000
1975	89800
1976	90000
1977	93600
1978	96500
1979	103700
1980	114400
1981	113800
1982	103900
1983	109100
1984	101400
1985	100500
1986	102300
1987	111800
1988	106200
1989	101600
1990	114000
1991	78500
1992	86300
1993	83300
1994	99500
1995	112400
1996	131400
1997	171600
1998	144600
1999	183600
2000	168815
2001	124493
2002	113178
2003	91657
2004	90518
2005	81298
2006	74162
2007	79465
2008	74649
2009	74546
2010	92847.5065402624
2011	90214.5205338809
2012	101716.268913446
2013	145136.020724733
2014	134521
2015	145585
2016	149334
2017	146631
2018	161862
2019	163106
2020	27447
2021	54218