Year	Number
1970	10057
1971	10164
1972	10088
1973	10133
1974	10420
1975	10685
1976	11713
1977	12157
1978	12368
1979	12563
1981	15760
1982	16348
1983	16268
1984	16443
1985	14641
1986	13120
1987	14137
1990	13877
1991	13839
1992	13318
1993	15573
1998	13086
1999	13814
2001	13297
2003	14627
2004	12911
2012	14503
2013	14433
2014	14484
2015	15401