#install.packages('dslabs')
library('dslabs')
library(ggplot2)

## Registered S3 methods overwritten by 'ggplot2':
##   method         from 
##   [.quosures     rlang
##   c.quosures     rlang
##   print.quosures rlang

library(extrafont)

## Registering fonts with R

library(ggthemes)

data1 <- greenhouse_gases
head(data1)

##   year gas concentration
## 1   20 CO2         277.7
## 2   40 CO2         277.8
## 3   60 CO2         277.3
## 4   80 CO2         277.3
## 5  100 CO2         277.5
## 6  120 CO2         277.6

plot <- ggplot(data1, aes(year, concentration)) +
  geom_line() +
  facet_grid(gas ~ ., scales = "free") +
  xlab("Year") +
  ylab("Concentration") +
  ggtitle("Atmospheric greenhouse gases")+
  theme_economist()

plot