Measles Cases vs. MMR Vaccination Coverage

Annual U.S. measles cases against kindergarten MMR vaccination coverage, both indexed to a common base year so two very differently-scaled measures (case counts vs. a percentage) can share one axis honestly. See measles cases and vaccination coverage for the real, unindexed series. Hover for the actual value and index at any year. A small coverage dip tends to line up with a disproportionately larger case increase, which is what you would expect once coverage nears the herd-immunity threshold, not a charting artifact.