Beginning July 1, 2006, and every year thereafter, the department shall determine the following information for each retired member or beneficiary whose retirement allowance has been in effect for at least one year:
The value of the ratio obtained shall be the annual adjustment to the original retirement allowance and shall be applied beginning with the July payment. In no event, however, shall the annual adjustment:
For the purposes of this section, "index" means, for any calendar year, that year's average consumer price index, Seattle, Washington area, for urban wage earners and clerical workers, all items, compiled by the bureau of labor statistics, United States department of labor.
RCW 41.37.160