It's three or four times as abundant as uranium, and about 400 times more abundant than U235. However, with fast reactors you can get power from all the uranium, not just the U235.

Uranium is currently a small portion of the cost of nuclear, so it can't be that hard to mine, especially after we only need 1% as much for the same amount of power.

Either keeps us going for thousands of years, and after that we could extract uranium from seawater until the sun goes out.