There are a huge amount of variations on the percentages, but the order is generally always the same. Invaluable.

You remember 10% of what you read.
You remember 20% of what you hear.
You remember 30% of what you say.
You remember 50% of what you do.
You remember 60% of what you write down.
You remember 70% of what you discuss with others.
You remember 90% of what you teach others.

This is why I find it very worthwhile to help other people with their revision - it helps me just as much as it helps them.