The ratio requirements are established by regions as follows: Western region—Garrett, Allegany, and Washington counties, 10:1; Central region—all counties on the western shore of Maryland, except Harford County and those listed in §A(1) of this regulation, 5:1; and Eastern region—all counties on the eastern shore of Maryland, and Harford County, 10:1. Only Class 3 land under Regulation .08 of this chapter may be used in developing the ratio requirement. Five acres or more must be actually devoted land. Examples of Ratio Requirements. A taxpayer owns a 401-acre parcel in the western region (10:1 ratio). None of the land is Class 1 or Class 2 land under Regulation .08 of this chapter. Twenty acres are actually devoted. There is a 1-acre homesite. The amount of actively used land eligible for agricultural use assessment is 220 acres, calculated as follows: A taxpayer owns a 400-acre parcel of vacant, passively used land. Because there is no actually devoted land, a ratio requirement cannot be met and no land qualifies for agricultural use assessment.