How much do you spend on social media?

I found an interesting article online today - As Social Spending Rises, Which Metrics Are CMOs Focusing On?

Whilst the article related to what SM metrics are used to convince management that spending on SM is the right thing to do, what I was fascinated with is that approximately 7% of marketing budgets are spent on SM, and this is considered lower than marketers had hoped! 

At the moment, I spend $0 but plan to increase this substantially within the next 6 months, as part of a digital strategy we're working on.

I'm curious, what percentage of your marketing budget is spend online, and in particular on SM? And, how is this determined?