title: Percentages for geom_text in stacked barplot with counts
body: <p>I want to have a stacked barplot with percentages in it based on counts.
  I have almost reached what I want but every value in the text is 100% instead of the real percentage ...
  I think there is one small mistake in my code but I can not find it.</p>
  
  <pre><code>
  ggplot(
    mtcars,
    aes(fill = factor(gear), 
        x = factor(carb))
  ) + 
    geom_bar(stat = "count", 
             position = "fill", 
             color = "black",
             width = 0.5) + 
    geom_text(aes(label = scales::percent(..prop..)), 
              position = position_fill(vjust = 0.5), 
              stat = "count") + 
    coord_flip()
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/znEAZ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/znEAZ.jpg" alt="enter image description here"></a></p>