Year	Percent change (Units)
1980	-5.564
1981	0.555
1982	3.137
1983	1.971
1984	5.362
1985	9.930
1986	8.479
1987	-1.178
1988	4.224
1989	5.398
1990	2.376
1991	4.031
1992	-0.131
1993	-1.415
1994	13.289
1995	7.003
1996	3.121
1997	9.208
1998	7.575
1999	2.553
2000	13.667
2001	2.395
2002	6.376
2003	-1.024
2004	7.137
2005	11.293
2006	13.965
2007	5.838
2008	4.770
2009	-11.944
2010	0.541
2011	7.444
2012	2.709
2013	1.471
2014	3.897
2015	4.561
2016	3.662
2017	4.183
2018	5.093
2019	3.011
2020	-2.787
2021	8.912
2022	6.300
2023	7.644
2024	6.289
2025	1.940
2026	1.940
2027	1.940
2028	1.940
2029	1.940