Year	%
1991	16.6666666666667
1992	16.6666666666667
1993	16.2162162162162
1994	15.9420289855072
1995	17.5925925925926
1996	18.8311688311688
1997	19.3693693693694
1998	20.327868852459
1999	21.6417910447761
2000	21.7472118959108
2001	21.6366158113731
2002	20.9090909090909
2003	16.6323377960865
2004	8.30193756727664
2005	6.70162116555174
2006	7.07920792079208
2007	7.98755186721992
2008	9.22701741059828
2009	10.7047594562458
2010	12.2450640052072
2011	13.6595729696102
2012	14.8857835301397
2013	15.9251250664272
2014	16.7844740536414
2015	17.5102953811513
2016	18.1423494251636
2017	18.5960802590267
2018	18.8218631157505
2019	18.8795557870569
2020	18.8150931292813
2021	18.6970896157892
2022	18.5144981356003