Beginning with the 15-cent printings, the numbers of actual stamps printed dropped dramatically. Over seven billion of the 2-cent watermarked printings were made compared to about 1.5 million unwatermarked and seven million of the watermarked 15-cent. Printed in a regal dark blue, these lovely stamps were most commonly used as payment for multiples of the 5-cent U.P.U. rate.
When the color of the 5-cent stamp was changed from brown to blue in 1898, the 15-cent was issued in olive green on watermarked paper to prevent confusion. Only about fifteen million copies were issued.
These 15-cent stamps, which depict U.S Senator and Representative Henry Clay from Kentucky, were most commonly used as payment for multiples of the 5-cent U.P.U. rate.