Year	Percent
1990	40.886
1991	41.223
1992	41.776
1993	41.766
1994	41.723
1995	41.646
1996	41.19
1997	41.715
1998	41.817
1999	41.728
2000	41.823
2001	42.945
2002	44.099
2003	44.836
2004	45.807
2005	45.983
2006	47.956
2007	49.462
2008	49.519
2009	49.693
2010	52.017
2011	53.484
2012	54.964
2013	56.614
2014	58.336
2015	59.988
2016	59.445
2017	59.185
2018	58.974
2019	58.85
2020	58.808
2021	58.364
2022	58.075
2023	57.96
2024	58.001
2025	58.15
2026	58.006
2027	57.905
2028	57.862
2029	57.894
2030	57.994