Is there any Bernstain type theorems for CMC hypersurfaces in $\mathbb{R}^{n+1}$ in the literature? 

More precisely I would like to know if there is an answer to the following

**QUESTION**: Let $f : \mathbb{R}^n \to \mathbb{R}$ be a smooth function such that $\mathrm{graph}(f)$ is a constant mean curvature hypersurface of $\mathbb{R}^{n+1}$. Is it true that $\mathrm{graph}(f)$ must be an affine hyperplane? 

I don't know much about CMC hypersurfaces and I don't where to look for an answer. Even if the question has a negative answer, I would like to know if there are counterexamples or if one can get an affirmative answer under some volume growth condition. 

Any help will be very much appreciated! 
Thanks!