Year	Percent
1990	51.458
1991	52.637
1992	53.579
1993	54.299
1994	54.919
1995	55.552
1996	55.825
1997	56.117
1998	56.37
1999	56.501
2000	56.456
2001	56.078
2002	55.439
2003	54.547
2004	53.406
2005	52.028
2006	51.06
2007	49.923
2008	48.644
2009	47.27
2010	47.935
2011	48.6
2012	40.24
2013	46.364
2014	52.6
2015	44.51
2016	43.542
2017	43.112
2018	42.682
2019	42.252
2020	41.823
2021	41.393
2022	40.963
2023	40.533
2024	40.104
2025	39.674
2026	39.244
2027	38.814
2028	38.384
2029	37.955
2030	37.525