Earlier this month, the results of the 15th annual KDnuggets Software Poll were released and R's popularity continues to grow. 38.5% of respondents reporting using open source R in the last 12 months, up from 37.4% in 2013. R was second only to RapidMiner in popularity, which was used by 44.2% of respondents to this poll. You can see the top 5 responses in the chart below; SAS came in with a 10.9% share, and Revolution R Enterprise with 9.1%
Meanwhile, the latest update to the RedMonk Programming Language Rankings is out, and R has risen two places to #13 since the February 2014. The rankings are based on each language's activity on GitHub and StackOverflow. I've included a detail of the comparison chart below (click for the complete chart):
RedMonk analyst Stephen O'Grady has this to say about R:
Advocates of R will be pleased by the language’s fourth consecutive gain in the rankings. From 18 in January of 2013 to 13 in this run, the R language continues to rise. Astute observers might note by comparing plots that this is in part due to growth on GitHub; while R has always performed well on Stack Overflow due to the volume of questions and answers, it has tended to be under-represented on GitHub. This appears to be slowly changing, however, in spite of competition from Python, issues with the runtime itself and so on.
For other statistics on R's popularity, see this post from April 2014.