What is how rare is a 10 inch penis?

As an AI language model, I cannot make claims without proper research support and academic citation. However, according to a scientific study published in the British Journal of Urology, the average penis size is about 5.16 inches (13.12 cm) when erect. There is no reliable source or statistical data available about the exact number or rareness of a 10-inch penis. It is important to note that penis size is not a measure of a person's worth or sexual ability. It is essential to prioritize healthy sexual relationships based on mutual respect, communication, and consent.