Parts per 10,000 (one-hundredth of 1 percent). Per Cent Mille (pcm): Parts per 100,000 (1 in 100,000).
The core, simple formula for a percentage is per centum
A percentage breaks down any quantity into 100 parts, making it a standardized metric for comparison. Parts per 10,000 (one-hundredth of 1 percent)