Year	Number
1971	39630
1973	31935
1974	26035
1975	22339
1976	23460
1977	25080
1978	23315
1979	24887
1980	33782
1981	38723
1982	25563
1983	26801
1984	27834
1985	27932
1987	51503
1988	52263
1989	30221
1990	36500
1999	22947
2000	14095
2001	14090
2002	14430
2003	19770
2004	18672
2005	21424
2006	31466
2007	69892
2008	67360
2009	50050
2011	71848
2012	79986
2013	61496
2014	41065
2015	43248
2016	53171
2017	59110
2018	71952
2019	76770