(1) For program year 2016, and all subsequent program years, ecology will determine market share by weight for all manufacturers using any combination of the following data:

(a) Generally available market research data;

(b) CEP sales data supplied by manufacturers for brands they manufacture or sell; or

(c) CEP sales data provided by retailers for brands they sell.

(2) Ecology will determine each manufacturer's percentage of market share by dividing each manufacturer's total pounds of CEPs sold in or into Washington by the sum total of all pounds of CEPs sold in or into Washington by all manufacturers.

(3) If CEP sales data is provided by manufacturers under subsection (1) or (6) of this section, ecology will exempt this data from public disclosure in accordance with RCW 42.56.270(13).

(4) Ecology will notify each registered manufacturer of their preliminary market share determination by June 1 of each calendar year.

(5) Manufacturers may challenge their preliminary market share determination by written petition to ecology. The petition must be received by ecology within thirty days of the date of publication of the preliminary market shares.

(6) The petition must contain:

(a) A detailed explanation of the grounds for the challenge;

(b) Detailed CEP sales data supporting the challenge; and

(c) Complete contact information for requests for additional information or clarification.

(7) Ecology will notify each registered manufacturer of their final market share determination by August 1 of each calendar year.