Year	HCB	PCB	Dioxins and furans	PAH
1990	100.0	100.0	100.0	100.0
1991	95.33	96.2	94.99	96.0
1992	97.74	92.4	89.52	103.0
1993	92.71	89.5	83.44	101.8
1994	85.45	85.9	77.01	92.3
1995	88.75	72.4	70.42	103.2
1996	88.17	67.2	62.1	87.5
1997	88.64	64.1	55.38	75.9
1998	93.1	60.4	49.28	71.9
1999	14.15	56.4	41.91	66.5
2000	11.81	37.4	37.52	58.9
2001	10.41	35.1	31.07	57.6
2002	8.43	30.5	24.51	39.1
2003	8.55	28.5	20.97	40.1
2004	7.41	28.0	20.47	38.4
2005	7.39	29.5	18.54	39.4
2006	5.42	30.4	18.53	40.5
2007	5.49	30.2	18.02	39.8
2008	5.04	30.7	18.21	39.1
2009	4.12	26.9	16.15	37.4
2010	3.73	24.5	16.65	40.2
2011	4.14	27.0	16.08	39.2
2012	3.72	23.0	14.8	36.7
2013	3.55	24.3	15.44	38.0