Not less than three-fourths of the directors of an incorporated domestic insurer shall be United States or Canadian citizens, and a majority of the board of directors of a mutual life insurer shall be residents of this state. The directors of a domestic insurer or domestic insurance holding corporation may be removed with cause by a vote of a majority of its voting capital stock or members (if a mutual insurer) at a valid meeting and said directors may be removed without cause by a vote of sixty-seven percent of its voting capital stock or members (if a mutual insurer) at a valid meeting.