title: ggplot2: display text labels from one group only
body: <p><strong>My setup:</strong></p>
  
  <p>I have a tibble of basketball players and their statistics.  </p>
  
  <pre><code>library(tidyverse)
  
  df &lt;- tibble(
    season = c(2010, 2011, 2012, 2013, 2014,
               2010, 2011, 2012, 2013, 2014),
    player = c("player_a", "player_a", "player_a", "player_a", "player_a",
               "league_avg", "league_avg", "league_avg", "league_avg", "league_avg"),
    fg_perc = c(.4912, .6083, .3095, .5525, .4289,
                .4825, .4836, .4819, .4860, .4848),
    points_game = c(20, 18, 15, 19, 18,
                    12, 12, 13, 11, 12)
  )
  </code></pre>
  
  <p>I've displayed a certain column (fg_perc) as a geom_line() for both player_a and league_avg.  I've also wrapped it in a custom function, as I'll be using the same method for other statistics.</p>
  
  <pre><code>make_chart &lt;- function(target_column) {
    df %&gt;% 
      ggplot(aes_string("season", target_column, label = target_column)) + 
      geom_line(aes(color = player), size = 1.33)
  }
  
  make_chart("fg_perc")
  </code></pre>
  
  <p><strong>My issue:</strong> </p>
  
  <p>I want to display the fg_perc values as percentages  for player_a data only. I can't figure out how to do this without eliminating the legend (when I spread() league_avg).  I'm looking for a solution that will also be able to keep non-percentage numbers as-is, and display them in similar fashion (e.g. points_game for player_a only). The output would look something like this (please excuse the MS Paint):</p>
  
  <p><a href="https://i.stack.imgur.com/4zvco.png" rel="noreferrer"><img src="https://i.stack.imgur.com/4zvco.png" alt="enter image description here"></a></p>
  
  <p>Thanks!</p>