Year	Percent
1990	51.997
1991	49.674
1992	52.365
1993	53.03
1994	54.394
1995	55.491
1996	57.404
1997	58.189
1998	60.295
1999	62.042
2000	62.302
2001	61.843
2002	63.554
2003	65.231
2004	67.664
2005	68.452
2006	69.283
2007	69.254
2008	69.601
2009	71.196
2010	72.396
2011	72.856
2012	74.046
2013	74.43
2014	75.681
2015	77.675
2016	77.828
2017	78.006
2018	78.175
2019	78.351
2020	78.544
2021	78.755
2022	78.984
2023	79.228
2024	79.475
2025	79.719
2026	79.96
2027	80.2
2028	80.443
2029	80.7
2030	80.975