Year	Percent change (Units)
1980	0.954
1981	-3.973
1982	-23.684
1983	-0.945
1984	3.170
1985	7.134
1986	-6.862
1987	0.112
1988	-2.668
1989	-2.992
1990	-12.606
1991	31.949
1992	24.984
1993	56.156
1994	6.213
1995	4.250
1996	5.612
1997	0.338
1998	-0.205
1999	-0.928
2000	-1.232
2001	-0.064
2002	-0.769
2003	-1.320
2004	-0.611
2005	-1.365
2006	-2.207
2007	1.569
2008	0.676
2009	-2.923
2010	4.484
2011	2.738
2012	-0.562
2013	-8.390
2014	1.011
2015	-1.906
2016	0.834
2017	0.432
2018	-1.170
2019	7.005
2020	161.645
2021	46.380
2022	100.718
2023	37.876
2024	42.667
2025	4.131
2026	21.109
2027	23.828
2028	14.569
2029	12.719