Year	Number
1971	279867
1972	343389
1973	382407
1974	543104
1975	583163
1976	669138
1977	719680
1978	751430
1979	787032
1980	820660
1981	850470
1982	884233
1983	929956
1984	963363
1985	1007642
1986	1037950
1987	1058012
1988	1076186
1989	1088712
1990	1114563
1991	1150637
1992	1197005
1993	1233282
1996	1274139
1997	1382868
1999	1405462
2000	1502296
2001	1631563
2002	1757505
2003	1809368
2004	1885134
2005	1950729
2006	1990067
2007	2057295
2008	2100630
2009	2120282
2010	2132908
2011	2166938
2012	2228398
2013	2433065
2014	2433877
2015	2400654
2016	2320081
2017	2262198