Year	Number
1986	16156310
1987	11244112
1988	8970208
1989	7170989
1990	8912822
1991	8022180
1992	8303535
1993	9744403
1994	11733142
1995	14638553
1996	16888140
1997	18920802
1998	15094010
1999	10625912
2000	9884275
2001	8721836
2002	8353827
2003	8052465
2004	8435149
2005	8451184
2006	9462197
2007	7411626
2008	7198407
2009	6500266
2010	6448642
2011	6115226
2012	5974500
2013	6253285
2014	5850866
2015	5797130
2016	5676256
2017	5433283
2018	5526688