Not sure if it's a coincidence or not but Sport England released the latest statistics today on participation. Here's my summary of the data in their release of those who participate, that is actually play according to their replies to the survey.
2013: 48,700 (year on year decrease of 9600)
2012: 58,100 (note, the Excel sheet on that page has a different date range while the PDF shows year on year)
2013: 166,400 (year on year decrease of 31,100)
I suspect these numbers are a lot more accurate than the numbers in the OP, but there must be some kind of problem with them. I don't think nearly half of all rugby players (both codes) have given up in the last few years.