My friend and I kept count as we passed out candy at my house. I think our final count was 8 Elsas (might have been 7) and 2 Annas. That's probably out of 50-75 kids.
We saw three Elsas, two Annas, and a baby Olaf (too cute!). We also saw two Ariels and an Aurora. A lot of kids were doing more traditional costumes. We saw lots of witches, skeletons, policemen, army men, firefighters, and black cats.
1 Elsa, 1 Anna...my daughters
We weren't home for trick or treating at our house but I doubt we would have gotten any as we only get our one neighbors and a bunch of teens most years since we are in a rural area and most kids don't actually ToT in the more spread out neighborhoods, opting to go to ones with houses closer together. We ended up going to grandma's house for ToT and saw lots of Annas/Elsas/Olafs but I didn't count them. I was disappointed in some of the adults for commenting 'Another Elsa!' when my 10 year old would walk up. She's already bordering the age of not wanting to be a 'princess' anymore and I could tell she felt a little self conscious when people did that. Let kids be kids and dress up in their favorite character without any comments other than how 'beautiful/scary/tough' they are.
Central Coast California....it hasn't rained here in almost a year. And when it finally did, it was yesterday on Halloween! My daughter, who was dressed as Elsa, was sooooooo disappointed. She did have a class party and there were 2 Elsa's in her class, including herself. I know we so desperately needed the rain but I wish it could of held off one more day.
We didn't have trick or treaters at our house since nobody in our neighborhood participates. We went to a Trick Or Treat on Main Street event and saw SO many Elsas! I think there were at least twenty of them and about half of them was going around with an Olaf or Anna or both. I was actually surprised by how many Olafs there were more than Annas.
My kids were Buzz and Jessie from Toy Story and we didn't see any others dressed like them. We did see a Woody though and my son was really excited about it.