Is there something like an "average frequency of rivers reaching the sea"?

[Lvl 2 Expert]

When I was talking about the Earth and the Sun being aligned, I certaily wasn't implying any third objects. Sure, two spheres are techically always aligned, but points on the surface of one sphere (in particular the Earth) are not necesarily aligned with the sun, the poles never are, and nor are any points outside a certain number of degrees (22 degrees?) from the equator.

My apologies, I see, you were just using a weird term for the sun being straight overhead or below a certain longitude, which could be considered an alignment of the tree objects earth, sun and a specific spot on the Earths surrface.