Youth Vote

[Mr. Morden]

It looks like it wasn't any better for Dems in House races.  In the national exit poll, among those 18-29, 56% voted Dem. in their House race, vs. 42% for the Republicans.  So even if Clinton wasn't strong among youngs (compared to expectations), it's not like the downballot Dems were doing any better.

[Mr. Morden]

Was the youth turnout lower than in 2012? One thing that strikes me is the relatively high percentage to minor parties (only 3% of voters over 40 voted 3rd party).

As a percentage of the electorate:

18-29:
2012: 19%
2016: 19%

30-44:
2012: 27%
2016: 25%

45-64:
2012: 38%
2016: 40%

65 and older:
2012: 16%
2016: 16%

Of course, as you said, 3rd party support was high among the young this time.  So fewer youngs were voting for one of the two major parties, as compared to 2012.

[Mr. Morden]

Aren't 18-29-year-olds a larger percentage of the population now than in 2012? Or is the difference negligible?

I don't know.  Just based on this:

https://populationpyramid.net/united-states-of-america/2012/
https://populationpyramid.net/united-states-of-america/2016/

I'm guessing the difference is pretty tiny.