National Referenda are governed by the Constitution. The Constitution provides that the a simple majority of the total number of votes cast and counted shall be required for a referendum to be adopted, however results are subject to review and confirmation by the Election Commission. Referenda may be initiated by the king if, in his opinion, a bill that fails in a joint sitting of Parliament is of national importance; if Parliament likewise insists on the passage of a bill not assented to by the king; or if an appeal is made by not less than fifty percent of the total number of members of all Dzongkhag Tshogdus. A National Referendum may not be held regarding taxes or any other grounds as might be prescribed by law made by Parliament, and a Referendum may not be withdrawn once initiated. Referenda are approved by a simple majority. The Constitution further mandates Parliament to prescribe the procedure for holding a National Referendum, which it has done; as of 2011, the National Referendum Act is available only in Dzongkha, however.