Year	Number of
1990	169.47
1991	174.7
1992	180.66
1993	187.2
1994	194.18
1995	201.57
1996	208.7
1997	216.27
1998	224.34
1999	233.11
2000	242.77
2001	251.51
2002	261.2
2003	271.78
2004	283.2
2005	295.53
2006	308.69
2007	322.77
2008	338.03
2009	354.36
2010	371.88
2011	384.95
2012	398.93
2013	413.73
2014	429.54
2015	446.45
2016	463.35