The history of exports from South Africa involves a single major exporter: the Cape Provincial Authority (CPA) which sent African clawed frogs all over the world. The CPA kept records, and these were summarised in a study which was published in April 2016 (but cited here as unpublished data):

Van Sittert, L. & Measey, G.J. (2016) Historical perspectives on global exports and research of African clawed frogs (Xenopus laevis). Transactions of the Royal Society of South Africa DOI:10.1080/0035919X.2016.1158747

In this paper, it is shown that X. laevis was sourced from King William's Town in the Eastern Cape, but that these animals were only used by tertiary institutions within South Africa.

Conflicts of interest: I am an editor of PeerJ I am an author of this PeerJ paper I am an author of the paper to which I refer