If someone touched infected surface every day during the past year, their risk of being contaminated would be about 3.6% according to this study (10^-4 at each contact). Touching twice per day would not double the risk, since the process is not linear. So 3.6% is a a kind of absolute maximum.

Note the paper suggest the real rate could be lower. For instance, a 10^-5 risk per contact would mean <0.4% risk for 365 contacts.