Year	Number of
1990	76.11
1991	77.88
1992	80.93
1993	84.09
1994	82.78
1995	82.64
1996	84.99
1997	87.12
1998	88.1
1999	91.88
2000	95.25
2001	97.68
2002	101.2
2003	103.96
2004	107.11
2005	108.76
2006	107.52
2007	109.42
2008	110.53
2009	117.62
2010	123.69
2011	130
2012	135.3
2013	143.84
2014	147.42
2015	149.96
2016	154.47