Beginning July 1, 2023, and subject to the availability of amounts appropriated for this specific purpose, rates paid under RCW
43.216.579,
43.216.585,
43.216.592, and
43.216.578 must be adjusted every two years according to an inflationary increase. The inflationary increase must be calculated by applying the rate of the increase in the inflationary adjustment index to the rates established in RCW
43.216.579,
43.216.585,
43.216.592, and
43.216.578. Any funded inflationary increase must be included in the rate used to determine inflationary increases in subsequent years. For the purposes of this section, "inflationary adjustment index" means the implicit price deflator averaged for each fiscal year, using the official current base rate, compiled by the bureau of economic analysis, United States department of commerce.