Senate constituencies were created by grouping all lower-chamber districts in a region, or by dividing a region into two constituencies of contiguous lower-chamber districts. The 1980 Constitution allocated a number of seats to appointed senators, making it harder for one side to change the Constitution by itself. The opposition won 22 senate seats in the 1989 election, taking both seats in three out of 19 constituencies, controlling 58% of the elected Senate, but only 47% of the full Senate. The unelected senators were eliminated in the 2005 constitutional reforms, but the electoral map has remained largely untouched (two new regions were created in 2007, one of which altered the composition of two senatorial constituencies; the first election to be affected by this minor change took place in 2013).