year	pollutant_name	index
1990	NMVOC	100.0
1990	NOx	100.0
1990	SOx	100.0
1991	NMVOC	94.5
1991	NOx	98.7
1991	SOx	95.6
1992	NMVOC	92.9
1992	NOx	99.8
1992	SOx	95.7
1993	NMVOC	88.1
1993	NOx	98.4
1993	SOx	99.1
1994	NMVOC	82.1
1994	NOx	95.1
1994	SOx	95.0
1995	NMVOC	77.9
1995	NOx	93.7
1995	SOx	89.6
1996	NMVOC	75.6
1996	NOx	93.9
1996	SOx	89.5
1997	NMVOC	71.0
1997	NOx	92.9
1997	SOx	87.0
1998	NMVOC	66.5
1998	NOx	92.7
1998	SOx	92.4
1999	NMVOC	61.8
1999	NOx	90.8
1999	SOx	88.2
2000	NMVOC	54.3
2000	NOx	86.5
2000	SOx	82.3
2001	NMVOC	49.7
2001	NOx	84.8
2001	SOx	85.3
2002	NMVOC	44.8
2002	NOx	82.0
2002	SOx	81.8
2003	NMVOC	41.1
2003	NOx	82.0
2003	SOx	87.9
2004	NMVOC	37.1
2004	NOx	82.8
2004	SOx	90.7
2005	NMVOC	33.1
2005	NOx	80.9
2005	SOx	88.2
2006	NMVOC	29.9
2006	NOx	81.3
2006	SOx	89.9
2007	NMVOC	26.6
2007	NOx	80.7
2007	SOx	90.2
2008	NMVOC	23.8
2008	NOx	76.8
2008	SOx	85.6
2009	NMVOC	21.3
2009	NOx	71.5
2009	SOx	81.3
2010	NMVOC	19.1
2010	NOx	68.9
2010	SOx	72.5
2011	NMVOC	18.0
2011	NOx	67.9
2011	SOx	73.3
2012	NMVOC	16.4
2012	NOx	64.2
2012	SOx	70.9
2013	NMVOC	15.1
2013	NOx	60.9
2013	SOx	58.3
2014	NMVOC	14.3
2014	NOx	59.9
2014	SOx	58.6
2015	NMVOC	14.2
2015	NOx	59.4
2015	SOx	51.3