Jim your circle of human contact appears limited, or perhaps ethnically shallow.

I have personally known the following from your list:

Cecil – white (an uncle – mom's side)
Percy – Mexican (not a shortened Percevil)
Colin – white, Hispanic, black (three separate people)
Derek – black
Leslie – white (four)
Maurice – black (best friend of a Leslie)
Nigel – Nigerian
Monty – Nigerian
Trevor – white
Zoe – white (one male, one female)
Madge – white
Mavis – black

How about? Sir Galahad (Filipino) and his brother King Arthur, their sister Gwendolyn
How about? Hansel (Mexican) – nope no sister.
How about? Vagina (black)

The world is becoming a United Nations of ethnic diversity.

It is full of wonder!!!

Sincerely,
Gargoyle