Annually, the Department of Finance shall transmit to each city and each county an estimate of the percentage change in the population of the city or the county. Such estimates shall indicate the percentage change in the resident population, excluding the population in state mental and correctional facilities and in federal correctional and federal military installations, of each city and each county between January 1 of the prior year and January 1 of the current year. Such statements shall be transmitted by May 1.
The Department of Finance may request data from any local agency to be used to prepare the population estimate required by this section. If any local agency fails to supply the requested data, the department is not required to provide an estimate for that agency, but may do so using the method deemed most appropriate by the department.