Year	Number of
1990	69.11
1991	72.68
1992	76.32
1993	79.32
1994	82.68
1995	85.1
1996	89.52
1997	95.24
1998	95.82
1999	101.12
2000	101.97
2001	106.43
2002	105.77
2003	108.86
2004	109.87
2005	114.33
2006	115.74
2007	118.52
2008	119.53
2009	122.56
2010	125.28
2011	127.86
2012	130.04
2013	132.1
2014	137.66
2015	140.87
2016	144.72