Year	Number of
1990	118.34
1991	122.41
1992	126.78
1993	133.12
1994	136.04
1995	138.92
1996	139.76
1997	141.72
1998	143.81
1999	146.18
2000	145.83
2001	149.65
2002	156.49
2003	151.1
2004	153.09
2005	155.17
2006	156.58
2007	157.83
2008	163.99
2009	172.81
2010	173.02
2011	174.16
2012	167.63
2013	164.38
2014	163.41
2015	168.86
2016	173.62