Year	Number of
1990	95.61
1991	96.2
1992	97.07
1993	98.04
1994	98.32
1995	101.51
1996	104.42
1997	108.92
1998	111.3
1999	111.8
2000	116.14
2001	117.69
2002	118.25
2003	119.05
2004	117.53
2005	119.74
2006	123.51
2007	127.79
2008	130.78
2009	135.63
2010	139.13
2011	141.7
2012	143.23
2013	144.8
2014	147.82
2015	150.61
2016	153.24