title: How to plot kernel density plot of dates in Pandas?
body: <p>I have a pandas dataframe where each observation has a date (as a column of entries in datetime[64] format). These dates are spread over a period of about 5 years. I would like to plot a kernel-density plot of the dates of all the observations, with the years labelled on the x-axis. </p>
  
  <p>I have figured out how to create a time-delta relative to some reference date and then create a density plot of the number of hours/days/years between each observation and the reference date:</p>
  
  <pre><code>df['relativeDate'].astype('timedelta64[D]').plot(kind='kde')
  </code></pre>
  
  <p>But this isn't exactly what I want: If I convert to year-deltas, then the x-axis is right but I lose the within-year variation. But if I take a smaller unit of time like hour or day, the x-axis labels are much harder to interpret.</p>
  
  <p>What's the simplest way to make this work in Pandas?</p>