How much content is in these?

[TON Collection]

[Conder101]

40% silver proof Bicentennial set.  They thought they would be a runaway sell out so the authorization law required them to strike all 15 million sets.  Sales were not a good as they had hoped and the sets were still on sale through 1982 when they finally pulled them and melted down the unsold sets.  Unfortunately they apparently didn't keep good records and even to day there still are no final mintage figures for these coins.  But they are not rare, just interesting.

[TON Collection]

Which is the rarest

[Conder101]

As compared to what?  The coins were only issued in the set so all three coins have the same mintage.