Year	Number of
1990	160.1
1991	162.86
1992	165.79
1993	168.63
1994	171.51
1995	174.9
1996	176.31
1997	178.31
1998	180.68
1999	183.34
2000	186.48
2001	192.15
2002	198.47
2003	205.32
2004	212.66
2005	220.76
2006	227.61
2007	234.68
2008	242.27
2009	249.97
2010	258.16
2011	263.73
2012	269.75
2013	275.92
2014	282.42
2015	289.25
2016	296.41