title: Figure captions with multiple plots in one chunk
body: <p>I label my figures like this.</p>
  
  <pre><code>---
  title: "xxx"
  output: 
    pdf_document:
      fig_caption: true
  ---
  </code></pre>
  
  <p>And then in each chunk</p>
  
  <pre><code>```{r, fig.cap="some caption"}
  qplot(1:5)
  ```
  </code></pre>
  
  <p>This works quite nicely. However in chunks where I plot multiple figures within a loop I can't specify a caption. This produces no caption at all:</p>
  
  <pre><code>```{r, fig.cap="another caption"}
  qplot(1:5)
  qplot(6:10)
  ```
  </code></pre>
  
  <p>How can I specify a figure that counts from the same number as the first chunk for each plot?</p>