Why does less than 5% of Mozart's music begin in a minor key?

I've actually thought of a more convincing reason for the strange figure. It may have something to do with the fact that much of Mozart's music is 'entertainment' music, that is, music that was composed not to be heard in a concert hall, but to form an agreeable background to feasting or socialising. The Serenades for Orchestra were largely composed for this role, as were the Divertimenti. I suspect this was simply the music people wanted to hear. Then again, this hardly accounts for the music that was specifically written for concert performance.

my point being that there is no "key" designated for each aria of an opera. so only looking for the word "mol" will not give you a truly representative idea of what portion of Mozart's music actually IS in a minor key.

In many cases, half the entire piece finds itself in a battle between major and minor, despite the initial key nomenclature. Sometimes, a movement is "in minor" but has a median section in the relative major. Sometimes a piece is notated as "in a major key" but has a minor slow movement.

quite honestly, this is the LEAST of my worries when thinking about Mozart's music.

I think the only reason I can't really hate Mozart is because of the Fantasia and Fugue for clock organ in F minor. Such a nice piece, though what the shit was he thinking. Clock organ. Any idea how much of a bitch that is to adapt to human-playable regular organ? And this is from someone who allegedly claimed the organ is the king of all goddamn instruments. If that's really what he said, I want to time-travel and force him to PROPERLY WRITE the damn thing at gun-point if necessary. What a jerk!

The clock organ is not a standard organ, and wasn't meant to be played by a human - that's why there are triple trills and things.
He wrote properly for proper organ - just not all that often.

I believe he wrote only two other works for solo organ: the Adagio and Allegro (also in F minor) and Andante in F. The other prominent organ works are his seventeen Church Sonatas (all of which are in a major key).

To me Mozart is one of the most dramatic composers, there is a lot of Major yes, but Mozarts exposition is allmost always in Minor. Mozart music is very special, there is a lot of smiles and tears at the same time. Listen 5 minuntes to Mozart and you have all the different state of mind, Its starts with a smile, then gets a little sad, then often angry or dramatic, then back to the smile again.

And if its in minor its the same way, even in Mozarts Requiem there is room for some smiles. I feel Mozarts music reflects life in every way. There is not just black and white. but grey purple etc. Listen to a Chopin Nocturne, its just the depressive crying beautiful melody, but often not the contrast, or not in the degree of Mozarts contrast.(mabye its just the difference of style). There surface of Mozart might seem Smile and simple. But there is just as much Minor in Mozart as there is Major, the contrast is allways there.

If you dive into Mozart you will find he's music very deep.
Listen to K.310 second movement, there you have a realy deep Mozart, full of emotion.

Most of the Mozart I actually like starts in a minor key...
The Piano Fantasy k.397 is one of my favorite pieces to (attempt) to play.