How do I say that something was decreased and became X times less? In a sentence like: The new file is 20K while the old file was 100K, that's a decrease in 5 times? Or: The file was 100K and it decreased by 5 times, becoming only 20K?
For instance, I found this topic where someone said:
"Decreased by 8 times" doesn't mean anything to me at all.
What are the most used and naturally sounding constructions for this types of sentences?