Year	Number of
1990	194.07
1991	184.59
1992	175.94
1993	168.18
1994	160.88
1995	154.12
1996	156.61
1997	159.49
1998	162.93
1999	166.7
2000	170.91
2001	178.07
2002	185.69
2003	194.16
2004	203.08
2005	212.62
2006	224.01
2007	235.74
2008	249.32
2009	263.8
2010	279.52
2011	291.86
2012	305.79
2013	320.98
2014	337.31
2015	354.76
2016	371.44