Year	Percent change
1980	30.2
1981	25.7
1982	28.9
1983	27.1
1984	36.1
1985	33.3
1986	32.4
1987	29.9
1988	31.2
1989	25.8
1990	36.4
1991	25.2
1992	20.7
1993	26.1
1994	37.9
1995	26.77
1996	21.049
1997	16.138
1998	12.778
1999	7.889
2000	5.956
2001	5.147
2002	4.555
2003	4.429
2004	4.138
2005	4.359
2006	7.251
2007	7.028
2008	10.276
2009	12.144
2010	7.192
2011	12.691
2012	16.001
2013	7.87
2014	6.132
2015	5.588
2016	5.168
2017	5.321
2018	3.509
2019	3.465
2020	4.53
2021	4.958
2022	4.903
2023	4.903
2024	4.903