Countries where elections are analyzed in this paper (first column).

Number of elections studied at the municipality scale (second column), and the date from which they are studied at national or provincial scale (third column) – even if it is before the end of the compulsory voting in Austria and in Italy. Star indicates that electoral data are also known at polling station level. Number of municipalities per country: in Austria (At); in Canada (Ca); in Switzerland (CH); in Czech Republic (Cz); in Metropolitan France (Fr); in Germany (Ge); in Italy (It); in Mexico (Mx); in Poland (Pl); in Romania (Ro); in Spain (Sp). See Appendix S1, Section A, for more details.