If your credit card is reporting a 0 balance to the CRA's, then your utilization is 0%. Some CCCs list the highest balance you've had on your account, but it isn't factored into the scoring equation unless your card does not report a credit limit. This is common with no pre-set spending limit cards. If the limit isn't reported, the scoring algorithm then uses your previous high balance to calculate your utilization.
Your utilization is the balance reported to the CRA's divided by the credit limit reported for that account.