title: How to remove the % lines in xtable table output by Knitr
body: <p>By using xtable and knitr, I add a table to my RMD document and export to PDF file.</p>
  
  <pre><code>```{r, results='asis'}
  library(xtable)
  xtable(matrixtable)
  ````
  </code></pre>
  
  <p>It looks great except there is a line</p>
  
  <pre><code>% latex table generated in R 3.1.0 by xtable 1.7-3 package % Wed Jun 25 13:34:57 2014
  </code></pre>
  
  <p>How can I remove this line. I tried to set <code>message=FALSE</code> but it doesn't work.</p>