Year	Number of
1990	174.7
1991	177.82
1992	182.52
1993	189.14
1994	196.26
1995	203.6
1996	210.22
1997	216.62
1998	223.48
1999	230.67
2000	238.5
2001	246.32
2002	254.62
2003	263.85
2004	273.41
2005	283.4
2006	293.43
2007	303.65
2008	314.95
2009	326.83
2010	339.49
2011	351.33
2012	363.8
2013	376.39
2014	389.65
2015	403.59
2016	419.67