Year	Percent change (Units)
1980	3.723
1981	3.940
1982	4.055
1983	-2.843
1984	-20.880
1985	-15.236
1986	2.367
1987	19.971
1988	12.449
1989	20.936
1990	6.238
1991	-2.973
1992	8.642
1993	14.213
1994	19.795
1995	15.612
1996	15.296
1997	14.997
1998	-14.144
1999	-24.090
2000	20.096
2001	2.791
2002	4.896
2003	5.768
2004	2.243
2005	6.642
2006	1.308
2007	1.033
2008	11.155
2009	-8.986
2010	18.487
2011	-0.026
2012	11.588
2013	-0.224
2014	15.861
2015	7.722
2016	18.173
2017	17.114
2018	9.734
2019	-1.379
2020	-23.498
2021	14.581
2022	14.780
2023	0.127
2024	6.039
2025	10.618
2026	9.999
2027	10.370
2028	9.957
2029	4.336