Year	Percent change (Units)
1980	13.984
1981	-22.402
1982	-4.589
1983	1.793
1984	-6.529
1985	21.783
1986	-26.189
1987	-2.863
1988	20.579
1989	21.257
1990	2.952
1991	-0.441
1992	14.966
1993	-7.781
1994	10.966
1995	-11.184
1996	9.706
1997	22.947
1998	-19.295
1999	14.330
2000	-21.679
2001	-6.363
2002	12.959
2003	6.550
2004	8.437
2005	3.538
2006	4.006
2007	-7.423
2008	32.451
2009	-24.925
2010	46.388
2011	-14.499
2012	-10.689
2013	-0.726
2014	10.504
2015	12.877
2016	3.969
2017	5.684
2018	-15.343
2019	14.342
2020	7.359
2021	-14.696
2022	-57.194
2023	75.974
2024	1.123
2025	15.454
2026	5.154
2027	5.997
2028	2.448
2029	2.538