Let's say that a novel consists of three parts: introduction, climax and conclusion. Is it ok if the conclusion is much shorter than the climax. For example, can the introduction be 20% of the novel, the climax be 78% of the novel, and the conclusion be 2% of the novel? Is it a bad thing? You would think a better distribution would be 20%, 60% and 20%. Not sure what the usual distribution is, but I am really wondering if it's ok to have a short and abrupt ending.
There are many ways to structure a literary work. For example in school I learned about the Dramatic Structure according to Freytag. Most books don't fall neatly in such a category though. And there certainly isn't something like a percentage you need to keep track of. I've written here on StackExchange about a similar topic when it comes to writing an essay and I can only repeat my personal motto for lots of writing related stuff:
It's not perfect when you can't add anything - it's perfect when you can't remove anything.
Try to make it meaningful. Try to bring your message across. Try to make it interesting.
And then leave it. If you start artificially inflating or deflating your work your readers will realize it and find those parts boring. They will think it's too drawn out or too abrupt.
But you need to make it as long as you need it to be to bring your message across. 2% sounds incredibly low and more like an exaggeration. I wouldn't worry about any kind of "usual distribution". Just write like you want it to be and like you need it to be for your readers to understand what is going on.
To give an example from running an RPG: you don't just say "Stones fall - everyone dies" and be done with the game. That's boring. That's uninteresting. That invalidates everything everyone participating has been working towards. It's a bad ending and people will remember it as such. You need some anticipation and some importance to the end that will justify what your characters have done throughout the book.