I believe the following may have complicated the analysis. Page 12 the circles represent “censor” https://static1.squarespace.com/static/5715352e20c647639137f992/t/5a4c48fb8165f5fe348889e3/1514948866948/2018Jan+IPIX+Corporate+Overview.pdf What is censor? http://www.statisticshowto.com/censoring/