Year	Percent
1990	3.61
1991	3.52
1992	3
1993	2.73
1994	3.47
1995	2.89
1996	3.32
1997	3.43
1998	3.79
1999	4.2
2000	4.47
2001	4.88
2002	5.54
2003	6.05
2004	7.71
2005	8.07
2006	8.93
2007	9.77
2008	11.12
2009	11.6
2010	12.33
2011	14
2012	15.04
2013	15.32
2014	15.98
2015	16.87
2016	18.22
2017	18.4
2018	18.58
2019	18.76
2020	18.941
2021	19.121
2022	19.301
2023	19.481
2024	19.661
2025	19.841
2026	20.022
2027	20.202
2028	20.382
2029	20.562
2030	20.742