However, the party soon found its main constituency in the industrial elites of the "industrial triangle" formed by Turin, Milan and Genoa. The PLI had its best results in the 1960s, when it was rewarded by conservative voters for their opposition to the participation of the Italian Socialist Party (PSI) in government. The party won 7.0% of the vote in 1963 (15.2% in Turin, 18.7% in Milan and 11.5% in Genoa) and 5.8% 1963. The PLI suffered a decline in the 1970s and settled around 2–3% in the 1980s, when its strongholds were reduced to Piedmont, especially the provinces of Torino and Cuneo, and, to a minor extent, western Lombardy, Liguria and Sicily.