# Date column in moderncv [duplicate]

I am writing my cv and with the following code

 \documentclass[11pt,a4paper]{moderncv}
\moderncvtheme[green]{classic}
\usepackage[utf8]{inputenc}
\usepackage{floatflt}
\usepackage{fancyhdr}
\usepackage{geometry}
\usepackage{tikz}
\usepackage{wrapfig}
\usepackage{lipsum}
\firstname{C}
\familyname{N}
\title{Curriculum vit\ae{}}
\photo[128pt]{picture}
\usepackage[english]{babel}

\begin{document}

\section{studies}

\cventry{Dec 01, 2010 -- Jan 01, 2011}{student assistant}{}{}{}{chair of statistics xxxx \newline student assistant as a tutor of statistics 2 }
\cventry{Jul 31, 2008 -- Sep 30, 2011}{matriculation Bachelor of Science x}{}{}{}{university of x}

\end{document}


I produce the following output

What I don't like is the line breaking of the date. In the first entry the "-" is in the second line and in the second entry it is in the first line. So I would prefer a more uniform formatting, so that the "-" is either in the first line or in the next line, but always the same and not switching. Any ideas?