Knitrexplore

library(historydata)
library(ggplot2)
data(us_national_population)
head(us_national_population)

##   year population
## 1 1790    3929625
## 2 1800    5308483
## 3 1810    7239881
## 4 1820    9638239
## 5 1830   12860702
## 6 1840   17063353

ggplot(data=us_national_population,
       aes(x = year, y = population))+geom_line()+geom_point(color= "red")