Other ggplot2 layers
A line plot is one way to display this data. You could also choose to display it as a scatter plot, with each year represented as a single point. This requires changing the layer (i.e. geom_line() to geom_point()).
You can also add additional layers to your graph, such as a smoothing curve with geom_smooth().
This exercise is part of the course
Case Study: Exploratory Data Analysis in R
Exercise instructions
Change the plot to a scatter plot and add a smoothing curve.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Change to scatter plot and add smoothing curve
ggplot(by_year, aes(year, percent_yes)) +
geom_line()