title: changing colors of geom_col ggplot2 to show categorical variable at 3 sites
body: <p>Long time fan of this site, first time user though.
  Been searching for a similar/working result for this question.
  I am trying to show the PROPORTION that each level of a 2 level factor appear at three locations. All in a side by side bar chart in ggplot.</p>
  
  <p>Here is the code I've been using to (try) to create the chart. The result has been two charts: one using geom_bar and geom_col, respectively. What I'd like is essentially a combination of the two. The first, but with the colors and Y axis of the second.</p>
  
  <p>Thank you!</p>
  
  <pre><code>    ggplot(df,aes(x = Stream,fill = death)) + 
      geom_bar(position = "dodge")+
      scale_fill_manual(values = c(rep(c("gray45", "gray75"))))+
      labs(fill="Time of Death") 
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/s0cB6.jpg" alt="enter image description here"></p>
  
  <pre><code>    death_stream &lt;-df %&gt;%
      group_by(Stream,Tree_Death)%&gt;%
      summarise (n = n()) %&gt;%
      mutate(rel.freq = paste0(round(100 * n/sum(n), 0), "%"))
  
  
      death_stream %&gt;% 
      ggplot(aes(x = Stream,y = rel.freq)) + 
      geom_col(position = "dodge",fill = "grey50", colour = "black")+
      labs(fill="Time of Death")
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/um3xm.jpg" alt="enter image description here"></p>