Year	Percent change (Units)
1980	-2.840
1981	19.183
1982	17.525
1983	-8.555
1984	6.058
1985	-6.477
1986	0.805
1987	-2.679
1988	-4.556
1989	-18.134
1990	21.841
1991	-21.027
1992	-55.779
1993	61.684
1994	-25.918
1995	54.065
1996	43.092
1997	19.741
1998	32.363
1999	11.413
2000	-4.907
2001	-8.865
2002	0.972
2003	4.216
2004	1.925
2005	13.711
2006	13.031
2007	8.201
2008	10.968
2009	14.647
2010	-3.611
2011	23.615
2012	-1.530
2013	21.945
2014	7.257
2015	8.509
2016	-1.524
2017	1.119
2018	4.813
2019	-3.120
2020	-39.318
2021	17.224
2022	-1.176
2023	-19.035
2024	-11.770
2025	10.016
2026	2.212
2027	2.294
2028	2.266
2029	2.268