Year	Percent change (Units)
1980	13.808
1981	7.300
1982	4.251
1983	2.103
1984	1.583
1985	1.027
1986	-0.066
1987	0.996
1988	0.359
1989	0.116
1990	0.769
1991	1.547
1992	1.751
1993	0.478
1994	1.332
1995	0.939
1996	1.264
1997	1.255
1998	0.628
1999	1.300
2000	1.446
2001	0.314
2002	0.998
2003	0.058
2004	0.475
2005	2.860
2006	2.458
2007	4.169
2008	8.759
2009	2.409
2010	3.491
2011	5.876
2012	5.698
2013	4.027
2014	2.623
2015	0.137
2016	0.740
2017	0.876
2018	0.762
2019	-0.355
2020	-1.550
2021	1.631
2022	2.860
2023	1.486
2024	1.735
2025	1.960
2026	2.000
2027	2.000
2028	2.000
2029	2.000