title: How to get a "events per month" bar plot in R
body: <p>im a newbie in R.</p>
  
  <p>I've got timestamps in a list in this style:</p>
  
  <pre><code> [1] "2011-10-04 17:23:28 CEST" "2011-10-04 17:26:13 CEST" "2011-10-05 16:17:34 CEST" "2011-10-07 09:59:37 CEST"
  </code></pre>
  
  <p>Now I want to plot a graph which shows me how many events occur in january, february and so on.</p>
  
  <p>Every timestamp represents one event and there may be months without an event (that should be shown as 0)</p>