Subject to the exceptions provided or permitted by law, the taxable status of persons and property shall be determined as of the thirty-first day of December, or such other date as may subsequently be required by law, which shall be deemed the tax day. Values on the assessment roll shall be determined according to the facts existing on the tax day for the year for which such roll is made, and no change in the status or location of any such property after that day shall be considered by the Assessor or the Board of Review.