Year	Number of
1990	285.5
1991	279.62
1992	276.51
1993	269.26
1994	257.61
1995	245.6
1996	245.69
1997	237.06
1998	224.56
1999	214.39
2000	200.9
2001	187.34
2002	184.24
2003	181.33
2004	182.17
2005	187.29
2006	184.28
2007	187.95
2008	192.67
2009	193.69
2010	194.07
2011	197.89
2012	199.13
2013	199.99
2014	198.77
2015	193.37
2016	191.07