The populations in grading companies’ censuses are influenced by not only actual population size, but by the value of the coins that are submitted. There is much greater motivation to spend the time and money to grade an expensive coin than there is to grade one that sells closer to its intrinsic, or melt, value. This means that a higher proportion of the population of the rarest and most desirable coins get graded compared to more common issues. In fact, a single rare coin may be submitted and counted multiple times (Arif is exemplary in informing grading companies of this for his own submissions, but many people do not). Relative to their true population rare coins are often overrepresented in census counts.
This can help to explain the price differences between coins with similar census populations. The grading censuses are useful tools, but in regards to population sizes they tell only part of the story.
Best wishes,
Peter Anthony
China Pricepedia — Chinese Coin Prices and` More
The Gold & Silver Panda Coin Buyer’s Guide
Home of the Valentine Panda
PCGS Consultant
www.pandacollector.com