Year	Number
1971	609205
1972	603326
1973	604007
1974	606446
1975	611372
1976	567014
1977	588416
1978	571249
1979	547517
1980	554681
1981	562725
1982	585332
1983	609324
1984	625951
1985	645530
1986	676781
1987	692027
1988	708865
1989	707343
1990	670529
1991	657476
1992	631354
1993	600396
1994	567504
1995	559399
1996	543212
1997	526792
1998	515283
1999	510106
2000	510321
2001	509339
2002	505533
2003	507904
2004	496064
2005	481281
2006	464375
2007	442622
2008	417775
2009	390423
2010	371857
2011	365043
2012	360862
2013	354985
2014	351279
2015	346266
2016	343688
2017	344423