The new PYPL Popularity of Programming Languages (June 2018) index ranks Python at #1 and R at #7.
Like the similar TIOBE language index, the PYPL index uses Google search activity to rank language popularity. PYPL, however, fcouses on people searching for tutorials in the respective languages as a proxy for popularity. By that measure, Python has always been more popular than R (as you'd expect from a more general-purpose language), but both have been growing at similar rates. The chart below includes the three data-oriented languages tracked by the index (and note the vertical scale is logarithmic).
Another language ranking was also released recently: the annual KDnuggets Analytics, Data Science and Machine Learning Poll. These rankings, however, are derived not from search trends but by self-selected poll respondents, which perhaps explains the presence of Rapidminer at the #2 spot.