Year	%
1988	47.94746
1991	46.36106
1993	44.00041
1996	35.75031
1997	29.45463
1998	34.76809
1999	35.1619
2000	32.70959
2001	30.2442
2002	30.60834
2003	29.70108
2004	32.54971
2005	32.84222
2006	26.01989
2007	26.83091
2008	23.9941
2009	23.05325
2010	22.3566
2011	27.41583
2012	27.33716
2013	25.57465
2014	18.43672
2016	22.78004
2020	21.77402
2021	21.98644