Add download statistics

Signed-off-by: Bruno Khélifi <khelifi@in2p3.fr>

news.html

@@ -93,7 +93,7 @@
 
         <br>
         <p>
-        <a href="#releases">Releases</a> | <a href="#news">News</a>
+        <a href="#releases">Releases</a> | <a href="#news">News | <a href="#stats">Download statistics</a>
         </p>
         <br>
 
@@ -455,6 +455,27 @@ <h2 id="2014"><a href="#2014">2014</a></h2>
                     href="https://github.com/gammapy/gammapy/commit/11af4c7436bb79f8e2cae8d0441693232eebe1ba">11af4c</a>)
             </li>
         </ul>
+
+
+        <br><br>
+        <h1 id="stats"><a href="#stats">Download statistics</a></h1>
+        <br>
+        <p>
+            Download statistics can be found using the <a href="https://pypistats.org/packages/gammapy">PyPI stats web site</a>:
+        </p>
+
+        <iframe src="https://pypistats.org/packages/gammapy" width="1000" height="800"></iframe>
+
+        <br><br>
+        <p>
+        Downloads are made also with <b>anaconda</b> via 2 channels and the statistics can be found here:
+        <ul>
+          <li><a href="https://anaconda.org/conda-forge/gammapy">conda-forge</a> </li>
+          <li><a href="https://anaconda.org/astropy/gammapy">astropy</a></li>
+          <!-- <li><a href="https://anaconda.org/OpenAstronomy/gammapy">OpenAstronomy</a></li> -->
+        </ul>
+        </p>
+
     </div>
 </main>