There's not a lot of data to work with as I don't have access to import records. I generally know the start and stop and serial number ranges for the importers and the associated countries. Here is a summary of what my research has found:
1) 100,000 select fire M14 rifles manufactured in 1960s at State Arsenal 356.
2) The select fire receivers are removed from the rifles in the 1980s. Most, but not all, of the select fire receivers do not leave mainland China. A few of the select fire receivers are part of complete rifles that do get exported. It's at least 500 but perhaps no more than 2000.
3) From 1987 to the current day, M14 rifles with semi-automatic only receivers and mostly 1960s parts are exported to several countries. Chinese M14 rifles have been exported directly from China to Germany, USA, Canada, New Zealand and I believe, Australia. The grand total export as of 2011 is estimated at about 62,000 complete rifles.
4) I estimate about 33,000 Chinese M14 rifles were exported to the United States from 1989 to 1994. Most of the remainder, about 29,000, have been exported to Canada with a few going to Australia, New Zealand and Germany.