Get total posts in community

Hi All, 

I am in the mid of redesign the whole community. I am wondering what RESTAPI call i can use to get metric data of total posts in our community. 

I can not find many documents in here :

http://community.lithium.com/t5/Community-API/bd-p/developers-rest-api?page=metrics

Thank you. 

Cheers,
Qing