Since 2008, the party has performed quite well in the opinion polls, ranging from 10 to 26 seats, compared to only 3 seats in the House of Representatives.Politieke Voorkeur sinds augustus 2008 on peil.nlTrends sinds de laatste tweede kamer verkiezing on politieke barometer.nl "Politieke Voorkeur sinds Januari 2009," Peil.nl (24 January 2010) In the 2009 European Parliament election, the party won 11% of the votes and 3 seats, two more than in the previous election. The news programme Nova attributed this increase to the leadership of Alexander Pechtold, who was considered "the leader of the opposition" at the time. "Alexander Pechtold is dé oppositieleider van dit moment," Hanneke van der Werf and Nynke de Zoeten, Nova: Den Haag Vandaag (19 April 2008) Under the leadership of Pechtold, the party has taken strong stances against the Party for Freedom (PVV) of Geert Wilders. Hugo Logtenberg, "Alexander Pechtold: Ik heb meer dan ooit criticasters nodig" on intermediair.nl (2 April 2008) In the 2010 general election, D66 increased its representation to 10 seats. In the 2012 general election, the party further increased its number of seats to 12. Since 2008, the party has experienced a significant increase in party membership, from 10,000 to 25,000 in 2015.
