https://www.cdc.gov/measles/data-research/index.html https://www.cdc.gov/measles/data-research/index.html Has a plot of cases over time, where you can clearly

https://www.cdc.gov/measles/data-research/index.html https://www.cdc.gov/measles/data-research/index.html Has a plot of cases over time, where you can clearly see the number of cases dropping after the vaccine is developed.