| year | pollutant_name | index |
|---|---|---|
| 1990 | SOx excluding international shipping | 100.0 |
| 1991 | SOx excluding international shipping | 95.4 |
| 1992 | SOx excluding international shipping | 96.3 |
| 1993 | SOx excluding international shipping | 93.8 |
| 1994 | SOx excluding international shipping | 90.7 |
| 1995 | SOx excluding international shipping | 77.6 |
| 1996 | SOx excluding international shipping | 70.8 |
| 1997 | SOx excluding international shipping | 54.5 |
| 1998 | SOx excluding international shipping | 54.4 |
| 1999 | SOx excluding international shipping | 50.3 |
| 2000 | SOx excluding international shipping | 40.3 |
| 2001 | SOx excluding international shipping | 37.8 |
| 2002 | SOx excluding international shipping | 32.7 |
| 2003 | SOx excluding international shipping | 32.9 |
| 2004 | SOx excluding international shipping | 31.1 |
| 2005 | SOx excluding international shipping | 25.3 |
| 2006 | SOx excluding international shipping | 24.4 |
| 2007 | SOx excluding international shipping | 22.3 |
| 2008 | SOx excluding international shipping | 19.6 |
| 2009 | SOx excluding international shipping | 17.4 |
| 2010 | SOx excluding international shipping | 14.8 |
| 2011 | SOx excluding international shipping | 13.8 |
| 2012 | SOx excluding international shipping | 11.9 |
| 2013 | SOx excluding international shipping | 11.9 |
| 2014 | SOx excluding international shipping | 12.0 |
| 2015 | SOx excluding international shipping | 10.7 |
| 2016 | SOx excluding international shipping | 11.8 |