grammatical function of "showing"

[hoangkha]

Hi!
I don't know the grammatical function of "showing" in the below sentence.
- Most age groups buy more fiction books than non-fiction ones showing that non-fiction is generally less popular than fiction.
Would you mind explaining it, please?

 

[Rover_KE]

It's the present participle, and there should be a comma before it.

 

[hoangkha]

It's the present participle, and there should be a comma before it.

Thank Rover very much.
Therefore, it should be
- Most age groups buy more fiction books than non-fiction ones, showing that non-fiction is generally less popular than fiction.
Could you please rewrite it so that it is easy for me to understand the syntax, Rover?

 

[Matthew Wai]

"..., their buying patterns show that non-fiction is ..."

Not a teacher.