An example of vote (in)efficiency in Quebec

I came across a remarkable contrast in vote efficiency in one of political analyist Patrick Déry’s recent newsletters: specifically, the case of the Parti Québécois in 1973 versus today. In the 1973 Quebec general election, the sovereignist party won just 6/110 seats in the province’s National Assembly with 30% of the vote. Today, according to projections, the party has a good shot of winning a majority with just 31% in the polls. A huge gain in vote efficiency, albeit one won over the course of half a century.