Session Ready
Exercise

Summarizing by year and country

You're more interested in trends of voting within specific countries than you are in the overall trend. So instead of summarizing just by year, summarize by both year and country, constructing a dataset that shows what fraction of the time each country votes "yes" in each year.

Instructions
100 XP

Change the code in the editor to group by both year and country rather than just by year. Save the result as by_year_country.