Year	Number of
1990	76.83
1991	78.38
1992	80.61
1993	83.76
1994	86.88
1995	89.27
1996	93.03
1997	98.84
1998	104.61
1999	111.62
2000	117.97
2001	123.97
2002	130.01
2003	136.9
2004	146.73
2005	157.5
2006	169.02
2007	181.84
2008	190.8
2009	201.42
2010	209.29
2011	213.86
2012	218.3
2013	223.03
2014	227.75
2015	232.56
2016	237.3