title: How to plot an histogram in R with several variables?
body: <p>i have to make an histogram  in r with the following data: </p>
  
  <pre><code>                     GDP: CONSTANT VALUES (2008=100)                                            
  
  **sector**  **2003**    **2004**    **2005**    **2006**    **2007**
  Agriculture   532918    543230        532043      562146    585812
  Mining        1236807   1258769     1263937      1250930    1235517
  Construction 1505948    1598346      1645017     1785796    1874591
  Manufacturing 6836256   7098173     7302589      7731867    7844533
  Wholesale      8635763  918174       966467       1037362   1070758
  </code></pre>
  
  <p>i know the rules and steps  to make an histogram of a very simple data (with only one variable expressed in a single year) like this:</p>
  
  <pre><code>age of members of group A in 2013
  12 13 13 57 57 90 56 32 12 34 
  16 23 23  23 14 67 89 90 35 92
  </code></pre>
  
  <p>the problem is that i am very confused because the former it´s a time series and it contains several variables and it´s quantity in several years and i do not know how to make one histogram to graph all the data together.</p>
  
  <p>could you please help me?</p>
  
  <p>many thanks in advance.</p>