The C919 with the LEAP-1C is not competetive enough to warrant those kind of numbers. I remember seeing a report somewhere where COMAC officials spoke of 1800 total upto 2042 with 700 aircraft of the standard length variant, 600 of the stretched variant - which means around 500 of the shortened High-altitude version (A319 analogue). More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.