Year	%
1972	55.52392
1985	69.21829
1986	70.99237
1997	68.75
1998	69.9163
1999	64.80076
2000	70.29504
2001	75.6502
2002	79.68652
2003	74.76315
2004	79.74945
2005	80.64969
2006	77.19955
2007	78.69707
2008	82.21692
2009	87.62269
2010	82.52737
2011	85.25321
2012	83.26431
2013	83.39534
2014	84.70092
2015	86.32489