Year	Percent
1990	49.916
1991	50.345
1992	50.995
1993	51.729
1994	51.857
1995	52.512
1996	53.129
1997	53.958
1998	54.669
1999	54.978
2000	53.794
2001	52.583
2002	50.859
2003	49.132
2004	47.413
2005	45.706
2006	50.448
2007	51.396
2008	52.346
2009	53.295
2010	55.161
2011	52.64
2012	50.082
2013	53.953
2014	57.741
2015	59.139
2016	60.093
2017	60.196
2018	60.297
2019	60.398
2020	60.5
2021	60.602
2022	60.705
2023	60.808
2024	60.911
2025	61.014
2026	61.117
2027	61.22
2028	61.324
2029	61.429
2030	61.535