 &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 11                                  &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 12                                  &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 13                                  &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 14                                  &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 15