Please allow me a few questions that possibly do no more than reveal my ignorance.
Although I don't know Tibetan, my impression from seeing passages of Tibetan quoted in secondary literature is that Indic loanwords in Tibetan are much, much rarer than they are in certain other languages of cultural areas that have also been in intense contact with Indian culture (e.g. the cases of Khmer and Javanese, where fully integrated loanwords, mainly from Sanskrit but also, to a much lesser extent, from NIA and NIA languages, may represent as much as 50% of all dictionary entries).
Questions to scholars of Tibetan among you: - can you confirm that the percentage of Sanskrit and other Indic loanwords in a Tibetan dictionary will be much lower than 50%? - are any precise figures known? - are there any general publications on loanwords in Tibetan? - has the relative openness or closedness of the Tibetan lexicon to the integration of loanwords been a subject of discussion among historical linguists?