or encumbrances, if any, upon such real estate does not exceed the appraised value thereof, except that the amount of any such loan hereafter made shall not exceed 662/3 per centum of the appraised value if such real estate is unimproved, 75 per centum of the appraised value if such real estate is improved by offsite improvements such as street, water, sewers, or other utilities, 75 per centum of