California Code, Civil Code - CIV § 1748.5

(a) A cardholder may request, not more frequently than once a year, that the card issuer inform the cardholder of the total amount of finance charges assessed on the account during the preceding calendar year and the card issuer shall provide that information to the cardholder within 30 days of receiving the request, without charge.

If the cardholder's request for the information is made in writing, the card issuer shall provide the information in writing.  However, if the card issuer is required to furnish the cardholder with a periodic billing or periodic statement of account or furnishes the billing or statement of account, the requested statement of finance charges may be furnished along with the periodic billing or periodic statement of account.

(b) This section shall not apply to card issuers or cardholders who issue or use credit cards in connection with a retail installment account, as defined by Section 1802.7.