How can I add labels to bar chart with ggplot2 if using a melted data.table?

I am using a melted data.table:

cat <- melt(as.data.table(insti), id.vars=c(1:3,11), measure.vars=4:10)

which I used to create a plot:

  ggplot(cat,
         aes(x=reorder(Llengua, -Publicacions),
             y=Publicacions, fill=Xarxa))+
  geom_bar(stat="identity")+#nº de publicacions
  theme_classic()+
  theme(axis.text.x=element_text(angle=90, hjust=0.8, vjust=0.5), legend.position="top")+
  labs(x="Llengua")+
  ggtitle("Catalunya")+
  geom_text(aes(label =Percentatge), vjust = 0.5)+
  theme(plot.title = element_text(hjust=0.5))+
  scale_fill_manual(values=col.Xarxa)+
  geom_hline(yintercept=0.333*sum(cat$Publicacions),
             linetype="dashed", color = "dark grey")

which looks like this: enter image description here

my question is: how can I add percentage or absolute values labels for every single column (don't take in consideration the color divisions) if every column comes from the total sum of several rows?

I added a Percentatge column to my data.table (primitively) so my x values Català and Espanyol have the same percentatge: enter image description here

but when I try to add the labels to the graph, the number appears repeated as many times as rows contributed to the bar, so nothing can be read:

 p + geom_text(aes(label =Percentatge), vjust = 0.5)

enter image description here

what can I do to avoid the repetitions and to set its position on the bar?

Solution

Using these two posts I could answer my question:

adding overlap data label over bar chart

draw the sum value above the stacked bar

To just remove the overlaps you can use argument check_overlaps=T in geom_text() . However to solve my problem I had to create a new dataframe:

m3 <- aggregate(cat$Publicacions, by=list(Llengua=cat$Llengua), FUN = sum)
m3 <- as.data.frame(m3)

and use it in geom_text like this:

 + geom_text(aes(x=Llengua, y=x, label=x), data=m3, vjust=-0.2)