Year	Number of
1990	86.84
1991	90.35
1992	94.19
1993	98.44
1994	103.05
1995	107.9
1996	112.67
1997	117.81
1998	123.97
1999	129.56
2000	136.59
2001	143.86
2002	150.71
2003	159.75
2004	166.26
2005	174.01
2006	181.53
2007	189.3
2008	199.08
2009	206.59
2010	215.16
2011	224.35
2012	233.69
2013	243.26
2014	253.98
2015	264.32
2016	277.63