Reference For 20th Century Revenue Tax Rates?

I've got Mike Mahler's excellent reference on tax rates from the Civil War. Is there an equivalent reference for the documentary (and other) tax rates of the early 20th century?

I have never seen one, although if you have the time and a good law library nearby you could find the info eventually.

The reason I ask is that I stumbled across an unusual (to me at least) item.

I've mentioned in other sections of the forum about how I accidentally started collecting the U.S. half-cent postage dues on cover or card. After finding one locally, it occurred to me that while the stamps themselves (J68, J69, J79) are minimum catalog value stamps, you very rarely find them on cover, unless they are in even-numbered multiples paying a full-cent rate. Actual combination usages, or even more scarce solo usages, paying a fractional rate are more scarce than one would think. No, they aren't rare, but they are typically $20-$50 items, which is a complete disconnect from the catalog values of the stamps themselves.

Which leads me to the item below. I noticed it because I always pay attention to half-cent stamps now, and it occured to me that I had not seen a fractional documentary usage on document before. Plenty of R195 and R206 as used stamps, sure, but never on document.

Now, as 20th century revenues are most definitely NOT in my wheelhouse, I could easily be completely offbase with respect to thinking it's unusual, as admittedly I tend to pay much closer attention to 19th century material than 20th century material, but this is the first I recall seeing.

I'm curious as to whether or not the usage rate is legitimate. Based on the premium cost, 12.5 cents would be exactly 1/2%.

I don't really know how common they are on document, although I have seen them before. I suspect that they are not especially valuable, there are many millions of documents around from this era.

Frank Sente published the 1898 documentary tax rates in a 1998 American Philatelist article. Those same rates were re-enacted in 1914. In this case the rate on casualty insurance was ½ cent per $1 premium. For a premium of $25, the tax would have been 12 ½ cents as we see in the illustration. A nice use of the ½ ¢ stamp to make up the rate, not particularly rare.

A solo use, however, is a highly prized usage.

revenuermd, welcome to the forum and thanks for providing an excellent answer to the original question.

Ron is a revenue guru. I asked him to reply here, since 20th century revenues are not a strong point with me.

Ron is a national treasure in the field of revenue stamps.