At Obvious, we are about to have nine engineers to four designers, which is a lower design/eng ratio than we've had in the past (but much less than, say, early days of Twitter -- when we had basically no real designers).
As your product/service grows, I think it's natural to have a lot more people work on the back-end/infrastructure pieces, as the total work for that part outstrips the part that users see. So I expect this to change over time.
Also, different types of products call for different ratios of work (though, in general, more design resources are needed than used to be the case in pretty much every category).
What's your experience/ratio?