title: ggplot facet by column
body: <p>I have this dataset here and was wondering how to create a ggplotted graph where
  x = year, y = market_book_ratio, return_on_capital, return_on_equity, and return_on_assets. I know that's alota y variables, so I wanted to facet these variables. Ideally, my graph would have years on the x-axis and the y-values would be each variable for each facet with the company shown as different colors.... is this possible in ggplot?</p>
  
  <p><a href="https://i.stack.imgur.com/wQWBX.png" rel="noreferrer"><img src="https://i.stack.imgur.com/wQWBX.png" alt="enter image description here"></a></p>
  
  <p>I've tried:</p>
  
  <pre><code> data %&gt;% ggplot(aes(x = year, y = market_book_ratio, color = company)) +
           geom_line() +
           xlab("Year") +
           ylab("Market-To-Book Ratio") +
           facet_wrap(~.)
  </code></pre>