If everyone teleported to 1000 ft and fell, how many would survive?
From 1000 ft, you're going to have mostly fatalities. Those landing in water and trained to do so might live, there could be some lucky enough to hit enough tree branches or snow before hitting firm ground, etc. Odds are against it. Few of us have the right training. Without training, a drop of 150 feet into water has 0–4% survival chances.
If this wasn't announced ahead of time, even those with the right training might not have enough time to accept what's happened and react properly. You've only got about 11 seconds to realize what's happening and to orient yourself in the best way, possibly less depending on your orientation (standing upright results in a higher terminal velocity).
It should be noted that when you hear stories of people falling farther than that and surviving, they usually have a parachute that deployed but didn't open. This is still slowing them down, just not enough to make the landing easily survivable.
EDIT: Another point is that most cases of survival from anything close to these heights take medical attention, and if everyone fell, who's providing that attention?