For those getting emails to schedule the AT-SA today, you have a number of great resources here. Start by re-reading this thread. In terms of data, this is what you're looking at...
2016 AT-SA
~9,300 applicants took the AT-SA
5,243 applicants passed the ATSA (56% pass rate)
2,242 are in Pool 1
3,001 are in Pool 2.
2017 AT-SA
5,383 applicants will be taking the AT-SA
2,194 Pool 1
3,189 Pool 2
HR is instructed to only inform applicants if they pass or fail the AT-SA. In fact, if they accidentally tell you your score, they are suppose to notify the office of the deputy of human resource services of their infraction.
Within the 'Pass' category, there are two bands...
Band 1 - 80-100
Band 2 - 70-79
They will exhaust Band 1 prior to moving to Band 2. Last panel, they exhausted Band 1 applicants (~3,000), zero Band 2 applicants were given TOL's. Last panel, they hired enough to cover two fiscal years of hiring. This panel, they will only be selecting 1,400 applicants (~700 from each pool). By law, the amount hired from each pool can only differ by 10% (45% Pool 1/55% Pool 2 and vice versa).
For Veterans, your preference (+5 or +10) will be added to your AT-SA score.
For those who passed the AT-SA in 2016 and were not selected, I cannot stress enough, you need to re-take the AT-SA. If you choose not to, they will exhaust Band 1 again. If any spots are remaining, it is a random draw from the Band 2 applicants. For those that took it last year, you weren't far off, you know what you're up against, come prepared and give it hell.