Year	Number of
1990	175.32
1991	185.25
1992	196.56
1993	209.05
1994	221.82
1995	233.77
1996	243.99
1997	252.85
1998	261.22
1999	269.19
2000	277.36
2001	285.26
2002	293.02
2003	301.84
2004	312.44
2005	323.76
2006	333.89
2007	342.85
2008	351.61
2009	359.56
2010	367.67
2011	376.87
2012	388.49
2013	401.39
2014	415.12
2015	429.1
2016	444.63