Year	Number of
1990	121.18
1991	124.25
1992	130.3
1993	138.06
1994	146.52
1995	155.05
1996	157.96
1997	160.39
1998	162.26
1999	165.94
2000	169.67
2001	176.03
2002	183.95
2003	197.95
2004	217.75
2005	234.51
2006	254.49
2007	271.64
2008	295.84
2009	319.37
2010	342.27
2011	356.64
2012	369.02
2013	380.82
2014	394.34
2015	408.76
2016	423.69