Year	Number of
1990	144.87
1991	138.08
1992	135.96
1993	134.93
1994	132.39
1995	130.47
1996	130.31
1997	130.24
1998	128.34
1999	138.8
2000	148.85
2001	161.02
2002	174.07
2003	188.5
2004	206.54
2005	222.13
2006	234.84
2007	241.15
2008	248.54
2009	257.42
2010	269.44
2011	285.37
2012	302.7
2013	325.43
2014	347.62
2015	367.43
2016	391.28