(a) For purposes of this code, "assessed value" means 25 percent of full value to, and including, the 1980-81 fiscal year, and 100 percent of full value for the 1981-82 fiscal year and fiscal years thereafter; and, tax rates shall be expressed in dollars, or fractions thereof, on each one hundred dollars ($100) of assessed value to, and including, the 1980-81 fiscal year and as a percentage of full value for the 1981-82 fiscal year and fiscal years thereafter. (b) Whenever this code requires comparison