Does anyone know of research showing the different types of statistical software used? I'm looking to find out things like what percentage of people use SAS vs. Stata, R, or other packages. I'm be happy to see references not only for statistics users but users in other science fields that make heavy use of statistics.
Number of users is very difficult to determine for free software like R, since there are servers all over the world, so even if one kept track of downloads on one site, the rest would be unknown, and people can share copies around; a single download of R might potentially be used by hundreds of people. One can perhaps get some idea by tracking discussions on various sites or mailing lists, e.g. by looking at volume of questions on Stackoverflow (and various other fora, especially since some programs have dedicated discussion)
Bob Muenchen produces regularly updated measures. At the time of posting the most recent one was October 2015:
There's also other surveys. For example, David Smith posted about two such surveys in Novenmber 2015, here:
This site is primarily of concern for users of software for statistical purposes On this site as of today, 2019-01-19, the following package tags have the listed number of followers:
r 19572 Matlab 1158 Python 2253 Mathematica 43 SAS 597 SPSS 1613 Stata 1091 Fortran 5 C++ 39 Excel 359 Perl 5 Oracle 8
Any others you can think of, just search the tags for it.
The KDNuggets blog does surveys of software used as reported by participating data scientists. Typically, these surveys are annual. Note that the percentages they report are not the same thing as market share of software sales, it's just a proxy for that metric. Moreover, it may or may not reflect the specific languages that interests you.
Here is a link to the results from a recent survey report:
But they have many more trendable polls available. Check on their site.