This interactive chart shows the number of unique strategic nuclear platforms held by nuclear states since 1951—a measure of the diversification of that state's nuclear forces. Click country names to add or remove data from the chart; double-click to see only a particular state's nuclear platforms. Hover over the chart (or tap if using a phone or tablet) to see individual data-points.

As the chart shows, different countries have taken very different approaches to diversifying their nuclear arsenals. Interacting with the data can make these strategies more clear. Israel and China, for example, have taken similar paths in diversifying their forces, as have France and the UK.

Data are from Erik Gartzke, Jeffrey M. Kaplow, and Rupal N. Mehta. 2014. “The Determinants of Nuclear Force Structure.” Journal of Conflict Resolution. 58(3): 481-508. The study draws nuclear weapons estimates from a variety of sources, as explained in the associated data appendix. See also “Nuclear Deterrence and the Structure of Nuclear Forces.” Note that platform estimates are not available for all countries in all years.

See a problem with the data? Comments or corrections are welcome.