Jaar	Invoer	Uitvoer	Totaal
2009	399.977	418.683	818.660
2008	439.796	487.671	927.467
2007	482.512	537.757	1.020.269
2006	458.048	510.314	968.362
2005	441.069	499.919	940.988
2004	421.806	472.891	894.697
2003	419.650	462.003	881.653
2002	510.810	552.933	1.063.743
2001	527.311	569.467	1.096.778
2000	535.736	570.899	1.106.635
1999	507.941	533.211	1.041.152
1998	491.801	514.240	1.006.041
1997	492.803	499.452	992.255
1996	426.807	411.088	837.895
1995	424.426	417.867	842.293
1994	433.013	427.079	860.092
1993	389.184	384.302	773.486
1992	381.764	383.293	765.057
1991	369.383	378.931	748.314
1990	397.429	407.369	804.798
1989	355.463	409.966	765.429
1988	282.555	342.156	624.711
1987	273.967	328.979	602.946
1986	243.520	293.944	537.464
1985	205.116	254.503	459.619
1984	181.320	214.148	395.468
1983	140.517	139.585	280.102
1982	127.859	143.591	271.450
1981	130.759	146.010	276.769