It's a question we get asked a lot and probably for the first time here is some research which provides that answer as well as a comparative figure since 2012.
So on average research shows that you should spend 6.3% of revenues if you are B2B Product, 6.9% if you are B2B Services, 9.6% if you are B2C Product and 11.8% if you are B2C Services.
How much do you spend?
That means businesses that ended the 2017 fiscal year with a solid $10 million in revenue are planning to spend $790,000 to market their businesses in 2018. That also means for every $1 million in revenue, $79,000 will be spent on marketing (on average).
http://www.convinceandconvert.com/digital-marketing/boost-our-marketing-budgets/