r - How to put 'geom_text' percent based on each bar?

Question

For example, I have a data frame as below with columns gender, year, count.

gender year count  
Man    2020 220     
Man    2019 206     
Man    2018 216     
Man    2017 156             
Woman  2020 45      
Woman  2019 47

Then I would like to put '%' on each stacked-bar with 100% per each bar in total. I tried but what I can get is separated % based on total bars.

For instance, on year 2020 I would like to have 'Man' with % of (220 / 220 + 45), and 'Woman' with (45 / 220 + 45).

This is the code I tired.

ggplot(data = all_gen, aes(x = year, y = count, fill = gender)) +
  geom_col() +
  geom_text(aes(label = paste0(round(count / sum(count) * 100, 1), "%")), position = position_stack(vjust = 0.5), vjust = 0.5, hjust = 0.3, size = 4.5, col = "black") +
  labs(x = "", y = "Count", title = "Gender by year") 

What can I do?

Answer 1

You can calculate the percentage for each year and then plot it using ggplot2 :

library(dplyr)
library(ggplot2)

all_gen %>%
  group_by(year) %>%
  mutate(percentage = paste(round(prop.table(count) * 100, 2), '%')) %>%
  ggplot(aes(x = year, y = count, fill = gender, label = percentage)) + 
  geom_col() + 
  geom_text(position = position_stack(vjust = 0.5), 
            hjust = 0.5, size = 4.5, col = "black") + 
  labs(x = "", y = "Count", title = "Gender by year")

Maybe changing Y-axis to percentage instead of count would be a better idea.

all_gen %>%
  group_by(year) %>%
  mutate(percentage = round(prop.table(count) * 100, 2)) %>%
  ggplot(aes(x = year, y = percentage, fill = gender, 
             label = paste0(percentage, '%'))) + 
  geom_col() + 
  geom_text(position = position_stack(vjust = 0.5), 
            hjust = 0.5, size = 4.5, col = "black") + 
  labs(x = "", y = "Percentage", title = "Gender by year")