Why they prayed
This question is usually argued. Here it can be counted: all 320 prayers in the collection are tagged by what they ask for and what they do with words. Below is the tally, and every row leads into the catalogue where you can check it.
There are about 14 petitions for every thanksgiving. Ancient prayer barely thanks — it asks. That is not a reproach: their gratitude went into the offering rather than into words, and the offering came with no speech attached.
The top three are not farming and not war but the personal, the civic and the family. Ancient prayer turns out far more domestic than it is usually taken to be: marriage, childbirth, the household, office. Harvest and battle come after, not first.
Petition and invocation together cover nearly the whole corpus — two halves of one act: first the god is called by name and by every epithet, so the address cannot go wrong, then the business is stated. The oath stands apart: there the god is not asked for anything but taken as a witness.
The tagging is editorial, and one prayer often falls under several spheres, so the columns add up to more than the number of cards. The tally is recomputed each time the page is opened — the figures here are read from the corpus, not written into the copy.