Year	Percent change (Units)
1980	-5.862
1981	10.195
1982	-11.032
1983	2.014
1984	14.307
1985	-7.377
1986	-4.776
1987	14.844
1988	1.302
1989	16.377
1990	2.043
1991	9.376
1992	16.077
1993	6.754
1994	3.469
1995	13.587
1996	5.589
1997	9.088
1998	28.955
1999	23.412
2000	-4.584
2001	6.430
2002	11.061
2003	19.971
2004	22.136
2005	18.863
2006	20.854
2007	10.112
2008	10.556
2009	-4.152
2010	3.589
2011	6.243
2012	6.990
2013	-0.912
2014	14.569
2015	-0.975
2016	9.282
2017	14.258
2018	6.888
2019	3.019
2020	-0.189
2021	29.049
2022	17.572
2023	-5.205
2024	4.686
2025	8.261
2026	8.547
2027	7.532
2028	6.697
2029	7.257