Any single top selling prescription drug does roughly the same of the whole field, and likely twice as much of the yearly sales of homeopathy
The article also mentions a figure of $115 billion but it is referring to the global alternative medicine sector, and it is a projection.
The global expenditure for prescription drugs has almost peaked to 1 Trillion $US in 2011, and that's for drugs that require an Rx, then there's the OTC sector, which is roughly another 10-12%
Homeopathy does roughly $3 billion/year, at best. 300 times smaller than big pharma. Definitely "little", imo.