"As of February 2009, it is estimated that the SVP retains 22.8% of the popular vote, while the BDP holds about 4%. Basis of this poll was a representative sample of 1231 citizens queried in the period of 20 January to 10 February."
http://www.tagesanzeiger.ch/schweiz/standard/Umfrage-SVP-verliert-deutlich-Waehleranteile/story/29205310