A white paper for a proportional-only electoral system was presented to the Chamber of Deputies on 13 September 2005, only seven months before the 2006 general election. This reform, strongly backed by the centrist Union of Christian and Centre Democrats (UDC), proposed a 4% threshold before a party gained any seats, and a majority bonus of (at least) 340 seats for the winning coalition, the total votes for each coalition being the sum of the votes of those coalition parties which had won at least 4% of the national votes. The new proposal was approved by parliament.