Year	Number of
1990	169.11
1991	166.59
1992	168.04
1993	168.04
1994	167.75
1995	166.48
1996	163.96
1997	161.11
1998	158.95
1999	159.53
2000	159.43
2001	159.14
2002	158.74
2003	159.12
2004	152.15
2005	146.36
2006	154.28
2007	160.6
2008	166
2009	172.03
2010	174.61
2011	178.47
2012	183.9
2013	189.24
2014	195.17
2015	200.95
2016	206.69