How to force a y axis to minimum and maximum range in R?

If you look at the graph below (y axis), you will notice that the scale is from `0` to `0.20`. I have other histograms where the range is from `0` to `0.4`. I want to make all of them consistent from `0` to `1` and display the `y` axis from `0` to `1`. ``` conne <- file("C:Aisdefined.bin","rb") sd <- readBin(conne, numeric(), size=4, n=1440*720, signed=TRUE) y <- t(matrix((data=sd), ncol=1440, nrow=720)) r <- raster(y) f <- hist(y, breaks=10,main="sm") f$counts <- f$counts/sum(f$counts) dat <- data.frame(counts= f$counts,breaks = f$mids) ggplot(dat, aes(x = breaks, y = counts, fill =counts)) + geom_bar(stat = "identity",alpha = 0.8) + xlab("Pearson correlation")+ ylab("Frequency") + scale_x_continuous(breaks = seq(-1,1,0.250), labels = seq(-1,1,0.250)) + ggtitle("2011") + theme(axis.title.x = element_text(size = 20)) + theme(axis.title.y = element_text(size = 20)) + theme(text = element_text(size=20), axis.text.x = element_text(angle = 90, vjust=1,colour="black"), axis.text.y = element_text(colour="black")) + theme(plot.title = element_text(size = rel(2.5))) + scale_fill_gradientn(colours = "black") ```