Making the Y axis 100% in ggplot

Question

I am trying to force my y axis to be 0 - 100 as it is showing percentage. The code below gives me ay axis of 0-15 but when i add "+ scale_y_continuous(labels=percent)" which i thought was the solution it comes up with '0% - 1500%'? Can anyone help? Thanks

april_graph <- ggplot(data, aes(fill=year, y=value, x=treatment)) + 
geom_bar(position="dodge", stat="identity") + scale_fill_discrete(breaks=c('2016', '2017', 
'2018', '2022')) +
xlab('Treatment Type') + 
ylab('Species Richness (%)') + theme_classic() +
labs(fill = 'Year of Survey') 


april_graph 

Answer 1

The percent function you use ( labels = percent ) expects inputs to be between 0 and 1: 33% is the same as 0.33, not 33. You can divide by 100 inside aes , y = value / 100 and then use

scale_y_continuous(labels = percent, limits = c(0, 1))

(Instead of value / 100 , if you calculated the percents you very likely multiplied by 100 earlier in your code, and you can omit that.)

In setting limits like that, I usually like to remove the padding:

scale_y_continuous(
  labels = percent, 
  limits = c(0, 1), 
  expand = expansion(0, 0)
)

If you want more flexibility in the percent formatting, use the more fully featured scale::label_percent function. It's help page has nice example. You can customize how many digits of accuracy to show, whether or not to multiply by 100, etc. Something like below (with y = value , not y = value / 100

scale_y_continuous(
  labels = scales::label_percent(accuracy = .1, scale = 1), 
  limits = c(0, 100), 
  expand = expansion(0, 0)
)