All real property in this state subject to taxation shall be listed and assessed every year, with reference to its value on the first day of January of the year in which it is assessed. Such listing and all supporting documents and records shall be open to public inspection during the regular office hours of the assessor's office: PROVIDED, That confidential income data is hereby exempted from public inspection as noted in RCW
42.56.070 and
42.56.210. All personal property in this state subject to taxation shall be listed and assessed every year, with reference to its value and ownership on the first day of January of the year in which it is assessed: PROVIDED, That if the stock of goods, wares, merchandise or material, whether in a raw or finished state or in process of manufacture, owned or held by any taxpayer on January 1 of any year does not fairly represent the average stock carried by such taxpayer, such stock shall be listed and assessed upon the basis of the monthly average of stock owned or held by such taxpayer during the preceding calendar year or during such portion thereof as the taxpayer was engaged in business.