The open-source R language is the most frequently used analytics / data science software, selected by 49% of the 2895 voters of the 2016 KDNuggets Software Poll. (R was also the top selection in last year's poll.) Python was a close second at 45.8%, and SQL was third at 35.5%. (Respondents could select multiple tools in the poll, and 6 tools were selected on average.)
While this is a self-selected poll (not a scientific survey), the results have been remarkably consistent over the 16 years that it has been conducted. This year's top 10 is very similar to that in 2015, the notable changes being Python's leap from #4 to #2 ranking, and scikit-learn (the machine-learning library for Python) joining the top 10 at the expense of SAS (which drops to #18 this year).
2016 also saw increased use of Big Data tools (particularly Hadoop and Spark, the latter seeing a 91% increase in use) and Deep Learning tools. For details on those results and a complete analysis of the poll results, follow the link below.