Year	Number of
1990	171.57
1991	176.1
1992	175.94
1993	177.61
1994	185.88
1995	188.04
1996	190.11
1997	185.26
1998	182.74
1999	182.8
2000	178.39
2001	175.9
2002	184.15
2003	191.27
2004	200.44
2005	203.21
2006	211.79
2007	218.04
2008	217.88
2009	213.09
2010	210.88
2011	211.97
2012	212.84
2013	211.19
2014	211.31
2015	217.07
2016	214.85