error trying to build a histogram using r with the rStudio application

Question

Using ggplot2 I am attempting to create a histogram. I have a column that is full on the continents. I need to add all the continents which I attempted to do with the aggregate function.

data <- aggregate(country$continent,country["continent"], sum)
hist(data)

Error in Summary.factor(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, : ‘sum’ not meaningful for factors