Year	Percent change (Units)
1980	10.261
1981	15.072
1982	-0.635
1983	16.742
1984	9.413
1985	-7.633
1986	-1.830
1987	-16.467
1988	5.104
1989	16.727
1990	-1.238
1991	31.645
1992	-46.241
1993	12.646
1994	10.841
1995	20.199
1996	1.220
1997	26.015
1998	15.185
1999	2.199
2000	-7.855
2001	-2.736
2002	-0.013
2003	3.972
2004	10.434
2005	0.804
2006	-2.578
2007	-0.843
2008	-7.430
2009	-14.792
2010	-2.078
2011	0.251
2012	-1.789
2013	1.450
2014	1.174
2015	12.447
2016	6.171
2017	-7.205
2018	-8.235
2019	2.558
2020	3.395
2021	-11.446
2022	9.640
2023	5.151
2024	8.093
2025	4.033
2026	5.096
2027	5.030
2028	3.590
2029	3.862