Year	Percent change (Units)
1980	3.343
1981	17.140
1982	8.236
1983	-4.540
1984	6.829
1986	0.989
1987	-15.462
1988	13.404
1989	25.935
1990	9.453
1991	6.848
1992	3.659
1993	1.959
1994	4.776
1995	4.193
1996	2.537
1997	6.314
1998	-0.822
1999	2.824
2000	-1.857
2001	3.771
2002	0.507
2003	2.856
2004	3.897
2005	4.171
2006	7.457
2007	4.604
2008	7.379
2009	2.997
2010	5.579
2011	3.034
2012	6.264
2013	3.042
2014	1.646
2015	-1.737
2016	1.219
2017	3.471
2018	3.778
2019	0.680
2020	-0.322
2021	2.345
2022	4.395
2023	2.009
2024	2.722
2025	2.434
2026	2.498
2027	2.501
2028	2.502
2029	2.502