Year	Number of
1990	99.05
1991	104.7
1992	110.88
1993	117.78
1994	125.11
1995	132.82
1996	142.26
1997	152.01
1998	162.78
1999	174
2000	185.75
2001	198.78
2002	212.53
2003	227.57
2004	243.48
2005	260.32
2006	281.45
2007	304.06
2008	327.47
2009	351.76
2010	376.64
2011	395.57
2012	414.68
2013	432.94
2014	453.83
2015	478.72
2016	506.98