Please answer a question about the following article about Greece:

The coalition government led the country to the parliamentary elections of May 2012. The power of the traditional Greek political parties, PASOK and New Democracy, declined from 43% to 13% and from 33% to 18%, respectively, due to their support on the politics of Mnimonio and the austerity measures. The leftist party of SYRIZA became the second major party, with an increase from 4% to 16%. No party could form a sustainable government, which led to the parliamentary elections of June 2012. The result of the second elections was the formation of a coalition government composed of New Democracy (29%), PASOK (12%) and Democratic Left (6%) parties.

What led to the loss of power of traditional Greek parties?
their support on the politics of Mnimonio and the austerity measures