This would give you the asnwer:
ggplot(example.melt, aes(x=example.Category, y=value, fill = variable)) +
geom_bar(position = "fill", stat = "identity",color="black",width=0.9) +
scale_y_continuous(labels = scales::percent) +
geom_text(aes(label = paste0(value*100,"%")),
position = position_stack(vjust = 0.5), size = 2)
Plot would look like this: