Section 205. Membership.--All of the members of the planning commission shall be residents of the municipality. On all planning commissions appointed pursuant to this act, a certain number of the members, designated as citizen members shall not be officers or employees of the municipality. On a commission of three members at least two shall be citizen members. On a commission of four or five members at least three shall be citizen members. On a commission of either six or seven members at least five shall be citizen members, and on commissions of either eight or nine members at least six shall be citizen members.