How to add percentages on histogram

Question

I try to add percentages on the percentage histogram, my code is as follows, but it seems that something is wrong, I can't add the percentages to the graph correctly, and I can't get the perfect percentage histogram, please tell me what is wrong.

data<-data.frame(type=c("A","B","C"),
             loss=c(1.7,2.2,2.5,0.8,3.1,4.7,0.5,1.5,1.7,0.7,1.4,1.7),
             label=c("1","2","3","4"))
data<-data%>% 
      group_by(type)%>% 
      mutate(count=sum(loss))%>% 
      mutate(freq=round(100*loss/count,2))
ggplot(data,aes(label,loss ,fill=type))+
geom_bar(stat="identity",position="fill",alpha = 0.9)+
theme_bw() + theme(panel.grid=element_blank())+
theme(axis.ticks.length=unit(0.5,'cm'),
    legend.position = "top")+
scale_y_continuous(labels = scales::percent)+
geom_text(label = paste0(data$freq,"%"))

You seem confused regarding what a histogram is. – Roland Dec 12 '22 at 08:29 — Roland, Dec 12 '22 at 08:29

score 1 · Accepted Answer · answered Dec 12 '22 at 08:31

Your group_by variable must be "label".
Don't multiply variable with 100. Multiply this variable inside paste() function.
Use position_stack() function to center labels.

library(tidyverse)
data<-data.frame(type=c("A","B","C"),
                 loss=c(1.7,2.2,2.5,0.8,3.1,4.7,0.5,1.5,1.7,0.7,1.4,1.7),
                 label=c("1","2","3","4"))
data<-data%>% 
  group_by(label)%>% 
  mutate(count=sum(loss))%>% 
  mutate(freq=round(loss/count,2))

ggplot(data,aes(label,freq ,fill=type))+
  geom_bar(stat="identity",position="fill",alpha = 0.9)+
  theme_bw() + theme(panel.grid=element_blank())+
  theme(axis.ticks.length=unit(0.5,'cm'),
        legend.position = "top")+
  scale_y_continuous(labels = scales::percent)+
  geom_text(label = paste0(100*data$freq,"%"),  position = position_stack(vjust = 0.5))

I tried it and it's what I want, thank you very much for your answer — 吳海濱, Dec 12 '22 at 09:18

score 0 · Answer 2 · answered Dec 12 '22 at 08:32

In geom_text(), you need to specify position = position_fill(). You will probably also want to adjust the heights so that the text appears in the middle of each bar, which you can do with vjust:

ggplot(data,aes(label,loss ,fill=type))+
  ...
geom_text(label = paste0(data$freq,"%"),
          position = position_fill(vjust = 0.5))

How to add percentages on histogram

2 Answers2