message: Update dataset notes
diff: <tbody>
  <tr>
  <td>Release Date</td>
  - <td>February 2019</td>
  - <td>January 2019</td>
  + <td>May 2019</td>
  + <td>April 2019</td>
  </tr>
  <tr>
  <td>Data Points</td>
  - <td>1,762,257 (-0.2%)</td>
  - <td>42,930 (+726)</td>
  + <td>1,757,574 (-0.3%)</td>
  + <td>42,939 (+9)</td>
  </tr>
  </tbody>
  </table>
  