That the rate of inflation there matches fairly closely the rate of overall inflation, which is a far more likely explanation for the shape of the chart you showed, with one exception, the healthcare inflation rate is consistently higher than the overall inflation rate. Even in the years you claim are "low" the inflation rate is higher than regular inflation, a snowballing proposition which is why we have the unsustainable situation we have now.
http://inflationdata.com/inflation/images/charts/Articles/Decade_inflation_chart.htm