Section 26. The colonel may promote uniformed members of the state police who are eligible for promotion to the title of noncommissioned officer, lieutenant or captain. All promotions shall be based on the following factors which shall be marked on a percentage basis:

(1) a competitive promotional examination open to all members who have completed not less than one year of service in the next lower rank, or title, or, in the alternative, to have spent at least some time in the next lower rank and to have completed at least ten years of service as a uniformed member prior to the final date for filing applications for such examination;

[There is no clause (2).]

(3) longevity, based upon a granting of five percent for each year of service plus one-twelfth of such five percent for each additional full month of service, up to twenty years of service, computed as of the final date for the filing of applications for such promotions;

(4) for promotion to a position of a commissioned officer, an oral interview conducted by uniformed members of the state police, or by officers of the state police department holding a grade higher than that for which the examination is being given.

In ranking members for the purpose of promotion to a title below that of lieutenant, such factors for promotion shall be weighted as follows: written examination, fifteen; and longevity, five.

In ranking members for the purposes of promotion to the title of lieutenant or captain, such factors shall be weighted as follows: written examination, fourteen; longevity, four; oral interview, two.

No member shall be eligible for promotion unless he has attained a mark of at least seventy percent in the written examination. Any member who is a veteran shall have two points added to his examination score for the purpose of compiling an eligible list for promotion.

Prior to making any promotions in accordance with the provisions of this section, the colonel shall publish and distribute in the orders of the department for each title in the department a list of the members who are eligible for promotion to each such title in the order in which each member shall be considered for such promotion; provided that such order shall be based upon the final determination by the colonel in accordance with the provisions of clause (2) or (3) of the first paragraph. Each such eligible list for promotion shall be used by the colonel from which to fill vacancies for a period of two years from the initial date of said publication; provided, however, if a new eligible list shall not have been established after such two year period, each such eligible list shall continue to be used by said colonel for promotions until a new eligible list shall have been established. Any promotion to a vacancy occurring in any title for which an examination is conducted in accordance with the provisions of this section shall be made from the first three members on such list who is eligible for such promotion and is willing to accept such promotion.