<span class="op">)</span><span class="op">)</span></span>
<span><span class="co">#&gt;             Motors Cars LED lamps</span></span>
<span><span class="co">#&gt; Electricity      1    2         3</span></span>
<span><span class="co">#&gt; Electricity      4    5         6</span></span></code></pre></div>
<p>But <code>margin = list(c(1, 2))</code> is the default, so the code
can be simpler still.</p>
<div class="sourceCode" id="cb11"><pre class="downlit sourceCode r">
<code class="sourceCode R"><span><span