Year	Number of
1990	88.59
1991	90.62
1992	91.82
1993	96.2
1994	96.55
1995	98.46
1996	108.11
1997	114.14
1998	117.82
1999	125.93
2000	130.57
2001	132.53
2002	133.99
2003	138.42
2004	145.23
2005	151.1
2006	155.18
2007	157.29
2008	161.99
2009	167.82
2010	168.36
2011	169.34
2012	170.77
2013	170.32
2014	169.21
2015	170.03
2016	168.46