Year	Percent
1990	44.18
1991	43.986
1992	44.368
1993	44.984
1994	45.671
1995	46.062
1996	46.683
1997	47.086
1998	47.391
1999	47.914
2000	48.733
2001	49.297
2002	50.162
2003	51.208
2004	52.221
2005	53.078
2006	53.855
2007	54.559
2008	55.24
2009	55.954
2010	56.727
2011	57.618
2012	58.527
2013	59.424
2014	60.283
2015	61.075
2016	61.633
2017	61.753
2018	61.837
2019	61.932
2020	62.062
2021	62.218
2022	62.4
2023	62.596
2024	62.784
2025	62.955
2026	63.113
2027	63.259
2028	63.398
2029	63.538
2030	63.684