Access Group by precinct, calculate percentage of older voters

[Jane-in-NC]

Hello, I am new to access and trying to help with get-out-the-vote efforts. I have the database of voters in my county. I want to group the voters by precinct and then calculate what percentage of voters in each precinct are over (for instance) 60. I'm trying to use count and where - I can get my query to run and give me the number of voters per precinct who are over 60 - but I can't figure out how to ALSO get the total number of voters so I can compute the percentage. Thank you.