Year	Percent change (Units)
1980	17.628
1981	-2.165
1982	48.226
1983	-7.989
1984	-22.953
1985	-18.282
1986	-4.183
1987	-21.417
1988	-2.577
1989	-7.019
1990	-15.419
1991	29.618
1992	-15.690
1993	-1.650
1994	7.704
1995	71.049
1996	-0.603
1997	58.959
1998	10.813
1999	-11.927
2000	8.783
2001	12.772
2002	2.740
2003	-0.905
2004	10.389
2005	2.572
2006	4.553
2007	9.824
2008	4.729
2009	-20.348
2010	-21.954
2011	16.715
2012	10.745
2013	1.787
2014	-9.264
2015	17.069
2016	-0.703
2017	-15.169
2018	-3.747
2019	-10.106
2020	-11.798
2021	-0.072
2022	5.475
2023	-6.637
2024	2.607
2025	3.526
2026	2.003
2027	1.208
2028	1.220
2029	2.892