Year	Number
1980	116469
1981	91834
1982	84562
1983	88767
1984	72947
1985	74756
1986	61831
1987	51582
1988	58361
1989	49458
1990	44404
1991	37456
1992	35374
1993	33365
1994	33081
1995	34429
1996	37329
1997	41225
1998	40452
1999	44038
2000	47129
2001	45093
2002	46259
2003	42656
2004	36945
2005	33634
2006	28221
2007	27110
2008	25293
2009	23125
2010	23454
2011	24728
2012	27836
2013	29108
2014	30851
2015	31905
2016	33052
2017	34418