As of this morning, Rcpp stands at 2501 reverse-dependencies on CRAN. The graph on the left depicts the growth of Rcpp usage (as measured by Depends, Imports and LinkingTo, but excluding Suggests) over time.
Rcpp was first released in November 2008. It probably cleared 50 packages around three years later in December 2011, 100 packages in January 2013, 200 packages in April 2014, and 300 packages in November 2014. It passed 400 packages in June 2015 (when I tweeted about it), 500 packages in late October 2015, 600 packages in March 2016, 700 packages in July 2016, 800 packages in October 2016, 900 packages early January 2017, 1000 packages in April 2017, 1250 packages in November 2017, 1500 packages in November 2018, 1750 packages in August 2019, 2000 packages in July 2020, and 2250 package in March of last year. The chart extends to the very beginning via manually compiled data from CRANberries and checked with crandb. The next part uses manually saved entries. The core (and by far largest) part of the data set was generated semi-automatically via a short script appending updates to a small file-based backend. A (manually curated) list of packages using Rcpp is available too.
Also displayed in the graph is the relative proportion of CRAN packages using Rcpp. The four per-cent hurdle was cleared just before useR! 2014 where I showed a similar graph (as two distinct graphs) in my invited talk. We passed five percent in December of 2014, six percent July of 2015, seven percent just before Christmas 2015, eight percent in the summer of 2016, nine percent mid-December 2016, cracked ten percent in the summer of 2017, eleven percent in 2018—and passed 12.5 percent or one in every eight CRAN packages dependens on Rcpp along with the 2000 packages mark. Truly stunning. As before, there is more detail in the chart: how CRAN seems to be pushing back more and removing more aggressively (which my CRANberries tracks but not in as much detail as it could), how the growth of Rcpp seems to be slowing somewhat outright and even more so as a proportion of CRAN – as one would expect a growth curve to.
The Rcpp team continues to aim for keeping Rcpp as performant and reliable as it has been (and see e.g. here for some more details). A really big shoutout and Thank You! to all users and contributors of Rcpp for help, suggestions, bug reports, documentation or, of course, code.