Voters across Pennsylvania will choose Democratic and Republican nominees May 21 for a variety of races; in Philly, that includes mayor and City Council; in other counties, row offices, district attorneys, and county commissioners.

April 22 was the last day to register to vote, and this week the Pennsylvania Department of State released its latest numbers on voters across the state.

>> READ MORE: Pennsylvania, Polarized: How a blue wave and red response deepened the state’s political divisions

Here’s a look at some of the numbers.

How Blue Is Philly? Very.

Where Philly’s Republicans Live

Philadelphia suburbs have grown bluer over time

The suburban counties — Bucks, Chester, Delaware, Montgomery — have shifted in Democrats’ favor over time, and the change is clear in both election results and in voter registrations. Note: In the four charts below, numbers are as of the November elections of each year except 2019, which uses current registrations.

Spot something intriguing?

If you see something here you’d like to know more about — if the data spark a question, or something makes you say, “Oh, huh” — email reporter Jonathan Lai at jlai@phillynews.com.