#activate the package
library(ggplot2)

#load the dataframe
ID <- 1:200
values <- rnorm(200, mean=65, sd=15)
my.dataframe <- data.frame(ID, values)

#simple histogram with ggplot()
ggplot(my.dataframe, aes(values)) + 
  geom_histogram()

#same histogram but with 60 bins
ggplot(my.dataframe, aes(values)) + 
  geom_histogram(bins= 60)

#same histogram but with binwidth=10       
ggplot(my.dataframe, aes(values)) + 
  geom_histogram(binwidth= 10)