actually i have my own doubts on 25k left quota, because from all ITAs issued there would be around 10% of them through PNP so i think that will not count in because PNP has their own quota of 51k and some ITA would have been rejected due to some problem so we still have around 30k ITAs left and i don't think candidates over 400 crs are more then 12 to 15k
1 ITA does not mean 1 PR.
Positive side for those awaiting ITA:
1) People decline ITAs and re-enter the EE pool
2) ITAs are issued for people applying under PNP also
3) People who do not submit their application after receiving an ITA
4) People get rejected/refused by CIC after applying for PR
Negative side for those awaiting ITA:
1) The 72,000 PR limit includes primary+spouse, which means 1 ITA can also result in 2 PRs.
As we do not have data to figure out all the above points, so we cannot predict what are the actual number of ITAs remaining to be issued in 2017.
Also, the number of candidates in a particular CRS range is not constant, it keeps on changing due to the below factors.
Negative side for those awaiting ITA:
1) New profiles being created (everyday somebody in some part of the world is deciding to migrate to Canada)
2) Increase in CRS score of existing profiles due to IELTS improvement, higher education, more work experience, Provincial nomination, etc.
3) ITA received in previous draw has been declined by applicant (re-entering the EE pool)
4) Application refused by CIC (re-entering the EE pool)
Positive side for those awaiting ITA:
1) Profiles expiring after 1 year and not being recreated
2) Decrease in CRS score of existing profiles due to IELTS expired and lower IELTS score in subsequent test, age, etc.
As you can see, lot of factors affect the composition of the tool, hence it is not a steady static composition of applicants in the Express Entry system.