Year	Percent
1990	59.33
1991	59.418
1992	58.786
1993	58.249
1994	56.958
1995	55.91
1996	55.009
1997	54.067
1998	52.951
1999	51.814
2000	50.349
2001	49.534
2002	48.411
2003	47.293
2004	45.708
2005	44.35
2006	43.029
2007	41.26
2008	40.103
2009	39.555
2010	38.855
2011	38.119
2012	37.603
2013	37.136
2014	36.632
2015	36.199
2016	35.577
2017	35.263
2018	34.949
2019	34.635
2020	34.322
2021	34.008
2022	33.694
2023	33.38
2024	33.066
2025	32.752
2026	32.438
2027	32.125
2028	31.811
2029	31.497
2030	31.183