How to get percentage on y-axis in ggplot2?

Question

I am trying to get the percentage on the y-axis. But some I could not manage to get it.

df <- tribble(
  ~id,   ~min,    ~max,
  "1",     5,      40,
  "2",     5,      50,
  "3",     7,      70,
  "4",     8,      90,
  "5",    23,     100,
  "6",    18,      40,
  "7",    34,      50,
  "8",    84,     150,
  "9",    15,      70,
  "10",  100,      90,
)


outs <- cut(df$min, breaks = c(0, 5, 10, 15, 20, 40, 60, 80, 100))
library(scales)

table(outs) %>%                                         
  as.data.frame() %>% 
  ggplot(aes(x = outs, y = Freq)) + 
  geom_col(col = "black", fill = "steelblue4", alpha = .4) +
  geom_text(
    aes(label = Freq, Freq = Freq + 0.05),
    position = position_dodge(0.9),
    vjust = -0.4) +
  labs(x = "Min", y = "Number of ids") +
  scale_y_continuous(labels = percent)

And this is the result:

I want to have it in both geom_text and the y-axis. Do you have any suggestions?

Answer 1

You have to first calculate the Freq by dividing over the sum of observations.

You can also modify your geom_text to get label = paste0(Freq*100," %"). Finally, add some limits to the scale_y_continuous to get a y-axis from 0 to 100%

outs = table(outs) / sum(table(outs)) 

outs %>%                                         
  as.data.frame() %>% 
  ggplot(aes(x = outs, y = Freq)) + 
  geom_col(col = "black", fill = "steelblue4", alpha = .4) +
  geom_text(
    aes(label = paste0(Freq*100," %"), Freq = Freq + 0.05),
    position = position_dodge(0.9),
    vjust = -0.4) +
  labs(x = "Min", y = "Percentage of ids") +
  scale_y_continuous(labels = percent, limits = c(0,1))

Does it answer your question ?