Year	% of total
1991	43.23124147842079
1992	37.127271080313356
1993	36.09146137666573
1994	35.92602547898214
1995	35.18903936438506
1996	34.59135259336614
1997	33.37585298011937
1998	32.289380374081844
1999	31.585164473720365
2000	31.98615202681706
2001	31.3846096052583
2002	31.267466885526563
2003	31.300316589611555
2004	30.871195053278953
2005	30.456107392019803
2006	31.56246742384775
2007	31.426029775699917
2008	30.73055706990915
2009	29.220275125063694
2010	29.753142813175607
2011	30.467859765193477
2012	32.20710515610724
2013	31.638580726425634
2014	31.16775004780734
2015	33.515338007677535
2016	32.16265117646535