I recon the percentage for toothbrushes is higher, because proximity. Nothing wrong with giving your immune system a bit of a workout.
that is why its great to toss them into the dish washer to keep them clean.
The ex-boss of a friend of mine used to clean the toilet brush in the office dish washer.
Many stores in the US offer wipes near the front of the store to wipe down the cart handles. I'd recommend using them, especially since so many people carry around raw chicken / meat products that leak.