The polls shall open at 7 a.m. and remain open until 8 p.m. In any precinct in which all of the eligible voters have voted prior to the time for closing the polls, the precinct board may thereupon close the polls, canvass the votes and make the returns as required by law. However, regardless of the time of closing the polls, no totals of votes cast or other returns shall be announced or disclosed prior to 8 p.m.