By December 31, 2007, and after each decennial census pursuant to section 32-553, each educational service unit board, except boards of educational service units with only one member school district, shall divide the territory of the educational service unit into at least five and up to twelve numbered districts for the purpose of electing members to the board in compliance with section 32-553. Such districts shall be compact and contiguous and substantially equal in population. The newly established election districts shall apply beginning with the nomination and election of educational service unit board members in 2008.