PRI had a stronghold in a few states including Sinaloa, Durango, Zacatecas, Mexico, Puebla, Chipas and Yucatan. The support of PRI was evenly distributed among the rest of the states except to Mexico City and Quintana Roo where it obtained half of the votes compared to their perfomance in the states listed above.
Contribution to PRI's "per voter votes" from each state