Year	Number
1970	43969
1971	47198
1972	52330
1973	55893
1974	60441
1975	63492
1976	67345
1977	78538
1978	80479
1979	82616
1980	81656
1981	79314
1982	77442
1983	77188
1984	73961
1985	71686
1986	69719
1987	71059
1988	73765
1989	77711
1990	78110
1991	81090
1992	83591
1993	87661
1994	89581
1995	91104
1996	93037
1997	93839
1998	94364
1999	95187
2000	95448
2001	97647
2002	99687
2003	103847
2004	105988
2005	110287
2006	114657
2007	116706
2008	116503
2009	116226
2010	115003
2011	115289
2012	115677
2013	113872
2014	114239
2015	114311
2016	111863
2017	110582
2018	110715