Year	Percent
1990	53.013
1991	52.599
1992	52.338
1993	52.147
1994	51.907
1995	51.596
1996	52.423
1997	53.341
1998	54.373
1999	55.608
2000	57.086
2001	59.558
2002	62.021
2003	64.251
2004	66.075
2005	67.436
2006	68.312
2007	68.902
2008	69.217
2009	69.328
2010	66.542
2011	64.039
2012	65.586
2013	60.147
2014	56.891
2015	60.1
2016	59.906
2017	60.446
2018	60.977
2019	61.48
2020	61.948
2021	62.378
2022	62.771
2023	63.143
2024	63.517
2025	63.908
2026	64.307
2027	64.72
2028	65.142
2029	65.559
2030	65.961