Year	cubic meters
1961	4571.793099782042
1962	4529.5102862018475
1963	4483.837330552659
1964	4437.427117839489
1965	4389.905259719046
1966	4349.9812849642385
1967	4305.209303256941
1968	4256.962113037194
1969	4206.654340191159
1970	4158.486697678018
1971	4068.2327786029878
1972	4011.6430943762366
1973	3955.5870367133666
1974	3903.3423503567474
1975	3853.979009258512
1976	3812.901795610729
1977	3776.169734438668
1978	3741.9613098605028
1979	3710.415048753128
1980	3681.2862242845035
1981	3654.5669338183425
1982	3629.30452397029
1983	3604.1472838978434
1984	3580.8565742028427
1985	3558.512707200609
1986	3539.6190382114223
1987	3522.5978749723517
1988	3507.970435151495
1989	3493.9749246357737
1990	3482.4017233839227
1991	3468.748991642735
1992	3455.897126783203
1993	3444.712366517396
1994	3435.1084056303825
1995	3427.0594236164243
1996	3419.292763027108
1997	3411.155271028186
1998	3401.8987341772154
1999	3395.6929977651603
2000	3390.0175807888495
2001	3381.8590787186686
2002	3374.0044725175567
2003	3366.7924646486795
2004	3365.659317005972
2005	3365.3432258771413
2006	3363.211162732492
2007	3359.348755087851
2008	3357.7223710205135
2009	3358.1419322592487
2010	3357.5388459436244
2011	3363.763660400679
2012	3369.140242421393
2013	3374.0044725175567
2014	3378.484553254345
2015	3382.071872959942
2016	3383.801819383676
2017	3386.5734177613963
2018	3390.873031519348
2019	3395.639367305521
2020	3405.643864692977