The zoning map shall show by an appropriate symbol on the map the existence of conditions attaching to the zoning on the map. The zoning administrator shall keep in his office and make available for public inspection a Conditional Zoning Index. The Index shall provide ready access to the ordinance creating conditions in addition to the regulations provided for in a particular zoning district or zone. The Index shall also provide ready access to all proffered cash payments and expenditures disclosure reports prepared by the local governing body pursuant to § 15.2-2303.2. The zoning administrator shall update the Index annually and no later than November 30 of each year.