multilateral environmental agreements by type (agreement, protocol, amendment, total) and year agreed, 5-year running mean, cf. fig. 1 in Mitchell et al. (2020), data is also from Mitchell et al. (2020), see sources. Note that treaties are assigned to a year by the year of signature only, whether and for how long the treaties were in force is not taken into account.
Own work
User:DeWikiMan, data: Mitchell et al. (2020) (see sources)