I'm not sure about the above data - I would be very surprised if only 16,630 applicants had submitted their applications out of 47,876 total ITAs. According to the spreadsheet you linked to, the data are preliminary and subject to change, though I'm not sure what changes could be made that would account for the fact that, based on numbers from the past two years, it should be more like two thirds of ITAs result in a submitted application. I guess we'll only know for sure at the end of the year when they release the 2017 EE summary.
In terms of your coment about 2,3 or 4 people per ITA; that may well be the case in individual circumstances, but you may be surprised perhaps that in actual fact, when taking into account the fact that many ITAs do not result in PR (whether through rejection, withdrawn profiles, applications which timed out etc) the actual ratio is around 1.2 landed PRs (including dependents) per ITA. You can work this out simply looking at the EE year end reports which give stats on how many ITAs there were and the total number of landed immigrants.
The 1.2 ITA to PR numbers have held steady since 2014 and I'd be extremely surprised if they change much this year. On the basis of 1.2 PRs per ITA, 47,876 ITAs should equal 57,451 PRs. On this basis, it seems to me that IRCC aren't too far off their desired 2017 quotas: Their 2017 targets are for 122,000 landed PRs through PNP/FSW/FST/CEC (high end being 129,300). 5/12ths of the way through the year they have 57,451. If they keep the exact pace of ITAs going then by the end of the year they will be at 137,882 PRs.
If this is correct, perhaps we may see a slight slowing of the number of ITAs issued, but perhaps if fewer people than normal have been submitting applications following their ITA then perhaps not. I'm expecting that broadly things will stay the same for the next 6 months. I'll be expecting draws of around 3000-4000 candidates every fortnight and for CRS scores to gradually fall to around the 400 mark and settle there.
For the draw which will hopefully come today, I'd be expecting a number somewhere in the low to mid 430s with around 3500 ITAs issued.