Net change in the aggregate vote share for all parties included in the Class Bloc. For the definition of the class bloc and the identification of parties included in such bloc, the author relies on Bartolini and Mair (1990) and Bartolini (1983; 2000). This includes 'those parties which are the historical product of the structuring of the working-class movement' (Bartolini and Mair 1990 [2007], 46). Full list of parties in the class bloc can be found in the original codebook.