There are 30 teams in the NBA, therefore, 30 players were drafted in the first round.
57-60 players a year
You can get drafted into the NBA from Canada similarly to the way that players from the USA get drafted. Several players from Canada have played in the NBA such as Steve Nash, perhaps the most famous.
With each passing year, more and more international players are being drafted by NBA teams. For the 2009 draft, 13 international players were chosen.
All that are not in the NBA
UCLA and Kentucky are tied with 109 players drafted into the NBA as of October 2014. The University of North Carolina has had 105 drafted. The school that has had the most players drafted in the 21st century is Kentucky, with 22.
So many. This year 12 were drafted. I believe 6 were picked.