Year	Number of
1990	135.1
1991	136.47
1992	141.16
1993	144.25
1994	146.98
1995	151.05
1996	148.8
1997	150.39
1998	151.45
1999	156.17
2000	163.27
2001	171.67
2002	176.56
2003	182.01
2004	189.04
2005	195.79
2006	204.38
2007	211.36
2008	218.88
2009	226.66
2010	233.59
2011	242.8
2012	251.85
2013	261.51
2014	271.38
2015	282.56
2016	294.32