VK and PK originated the idea, set up the data collection, coded the findings, analysed the data and wrote the first draft of the manuscript. SM curated the records over a 28 year period and together with RS and TB participated in sorting records, data extraction and identification of endoscopists and contributors. CM, EP and PM carried out data extraction and entry. BK contributed a section on user fees which may contribute to selection bias, and together with ES, BA, IZ and JBN discussed the interpretation of the findings. All authors then went through and edited the manuscript through several revisions and approve the final manuscript.