Year	cubic meters
1961	21289.91461790958
1962	20833.138994350178
1963	20393.392946523993
1964	19964.087817486517
1965	19543.888426760735
1966	19145.19711139298
1967	18766.207444395775
1968	18403.478410018815
1969	18054.681432182362
1970	17977.126119377957
1971	18009.88124230548
1972	17823.65488674811
1973	17599.775843650947
1974	17444.363185277074
1975	17925.296993633398
1976	19121.241035134564
1977	19966.23620057425
1978	20230.849764468287
1979	19927.928975935785
1980	19454.879440241497
1981	18948.940304867396
1982	18218.35101565796
1983	17524.072350297778
1984	16905.20148939591
1985	16350.12587970049
1986	15741.418870933026
1987	15121.12510198296
1988	14583.217449557304
1989	14070.82173598938
1990	13534.126198207838
1991	13024.65547842281
1992	12409.686346721079
1993	11773.262199139945
1994	11338.472876934415
1995	11044.433422397013
1996	10784.600234721547
1997	10549.732936922308
1998	10335.00764456349
1999	10135.30037719117
2000	9951.44667712036
2001	9774.527742800567
2002	9600.551004758163
2003	9430.93016654272
2004	9265.25526969076
2005	9104.234654325572
2006	8948.061843127121
2007	8793.426017210179
2008	8648.950708726288
2009	8519.512226135828
2010	8396.263537408486
2011	8275.075588973015
2012	8156.011101913619
2013	8040.169915590883
2014	7928.568202483799
2015	7822.268207415679
2016	7718.605500152837
2017	7618.114410560399
2018	7525.629260545147
2019	7440.886598296887
2020	7355.06676278263