ggplot in R - historam & line plot with two y-axis

Question

I am trying to create something like this:

Insired by this question i tried the following, but i does not work:

claims_freq  <- c(0.1,0.3,0.2,0.7,0.1)
claims_sev <- c(10000, 12000, 14000, 16000, 1600)
year <- c(2015, 2016, 2017, 2018, 2019)
data <- cbind(claims_freq, claims_sev, year)
data <- as.data.table(data)

twoord.stackplot(lx=data$year, rx=data$year, 
                 ldata=cbind(data$claims_freq),
                 rdata=cbind(data$claims_sev), 
                 lcol=c("black"),
                 rcol=c("black"), 
                 ltype=c("l"),
                 rtype=c("bar"), 
                 lylab="freq", rylab="sev", 
                 xlab="year",
                 main="Freq/Sev 2015-2020",
                 border="grey80")

is it possible to do this in ggplot?

Answer 1

Try:

#It has to be in data.frame format
data <- data.frame(year, claims_sev, claims_freq)

#column plot + line plot
ggplot(data, aes(year)) +
  geom_col(aes(y = claims_sev), fill = "#D17F7D") +
#adding line plot - x times the value (e.g. 30 000)
  geom_line(aes(y = claims_freq*30000), color = "#227BC4") +
#adding second axis + dividing main axis by x
  scale_y_continuous(sec.axis = sec_axis(~./30000))
#you can use `labels()` and `theme()` for further adjustments

Result: