Year	Number of
1990	1.85
1991	1.84
1992	1.82
1993	1.79
1994	1.79
1995	1.84
1996	1.96
1997	2.1
1998	2.1
1999	2.08
2000	1.98
2001	1.94
2002	1.98
2003	1.97
2004	2
2005	2.1
2006	2.04
2007	2
2008	2.04
2009	2.09
2010	2.01
2011	1.88
2012	1.79
2013	1.73
2014	1.74
2015	1.79
2016	1.86