Indices of clean air policies in existence from 1993-2000 in percentage terms
| 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | |
| Worksite full | ||||||||
| Private firms | 59.5 | 63.5 | 67.5 | 71.5 | 72.9 | 74.3 | 75.8 | 75.8 |
| Laws | 11.3 | 15.5 | 15.8 | 15.8 | 16.7 | 17.2 | 17.2 | 17.2 |
| Final index | 50.9 | 55.3 | 57.4 | 60.2 | 61.0 | 61.9 | 62.5 | 62.3 |
| Worksite partial | 81.7 | 83.7 | 84.8 | 86.2 | 87.3 | 88.5 | 89.6 | 89.5 |
| Restaurant | 17.2 | 19.0 | 19.5 | 19.7 | 19.9 | 20.8 | 20.8 | 20.8 |
| Other places | 12.8 | 13.1 | 13.5 | 13.5 | 13.0 | 13.7 | 13.7 | 13.7 |
| School | 38.5 | 45.7 | 45.7 | 45.7 | 45.7 | 45.7 | 48.2 | 48.2 |
Indices are weighted averages of state and local laws multiplied by 100, except for worksite which is a the law index multiplied by a private index of the percent of workers in firms that have total or partial ban smoking bans. See text for details.