Year	% of total
1990	79.2815229708655
1991	78.69128866975844
1992	79.03287707494688
1993	79.04761200480499
1994	76.86943737662924
1995	75.75941824896078
1996	73.69343368183989
1997	72.45776916948876
1998	72.49042701551458
1999	74.06632561303427
2000	69.94871599285479
2001	71.25086947635188
2002	69.41357642413638
2003	67.94199797381847
2004	67.2099549283221
2005	67.83145763629014
2006	65.96937755743134
2007	64.63464652402834
2008	64.61014986944244
2009	64.99083811839255
2010	62.958893088529365
2011	62.07479409117991
2012	63.187711477689334
2013	63.138387957282696
2014	62.74761771497012
2015	61.02101968342361
2016	60.75416751996505