How long does it take to swim 1 mile of breastroke?

I used to be a competitive swimmer. Now I am much older, I start swimming again just for fitness and I would like to set a goal for myself. My goal is to swim 1 mile of breastroke (breastroke is my specialty) daily; it takes me 35 minutes to swim 1 mile. My question is what is the average time to swimm 1 mile of breastroke? Thanks