Year	Percent change (Units)
1981	10.966
1982	16.601
1983	-0.173
1984	-3.132
1985	4.573
1986	1.403
1987	-0.498
1988	0.691
1989	-2.981
1990	1.534
1991	5.035
1992	-2.109
1993	2.351
1994	48.498
1995	6.393
1996	4.906
1997	3.032
1998	-1.391
1999	4.511
2000	-1.231
2001	6.561
2002	1.476
2003	-1.675
2004	3.667
2005	3.575
2006	0.649
2007	3.038
2008	8.698
2009	1.753
2010	1.556
2011	1.461
2012	2.909
2013	-0.504
2014	1.831
2015	1.624
2016	0.438
2017	-0.680
2018	1.989
2019	-0.329
2020	3.537
2021	6.157
2022	7.716
2023	2.613
2024	2.159
2025	1.839
2026	2.000
2027	2.000
2028	2.000
2029	2.000