Add vertical line between line numbers and file contents

I have set number in my ~/.vimrc, which enables line numbers. Generally they are quite useful, but it can be a bit tricky to discern the actual contents of a numerical data file from the line numbers, even if the line numbers have a different color.

Is there something like a vertical line to separate line numbers from file contents? For example, image on the left is the original state, and in the right the desired result after enabling the vertical line:

 

The line does not need to be the perfect, continuous line depicted. It could be an ASCII line formed by pipe characters (|), for example, which I guess to be more reasonable in a terminal or Gvim.