In this subchapter:
(1) "Consumer price index" means the average over a calendar year of the Consumer Price Index for All Urban Consumers (CPI-U), U.S. City Average, published monthly by the United States Bureau of Labor Statistics, or its successor in function.
(2) "Firefighter" has the meaning assigned by Section 607.051.
(3) "Peace officer" has the meaning assigned by Section 607.051.