ggplot - grouped marplot for 2x2 table : Given a contingency table 2x2 with the counted numbers in cells, how can I get a grouped bar plot with stacked percentages?

Here is an example code

    specie=c(rep("sorgho" , 1) , rep("poacee" , 1)  )
    condition=rep(c("normal" , "stress") ,1)
    value=abs(rnorm(4 , 0 , 4))
    data2=data.frame(specie,condition,value)
    
    # Stacked Percent
    ggplot(data2, aes(fill=condition, y=value, x=specie)) + 
      geom_bar( stat="identity", position="fill")

But my data looks like:

      
            A B
    Group C 4 5
          D 1 2

The plot should tell me: What's the percentage of A is in Group C? What's the percentage of B is in Group D?

Thanks.