The top 10% of the most prolific elite can be credited with 50% of all contributions.

From Age and outstanding achievement: What do we know after a century of research? by Dean Keith Simonton.

A small percentage of workers is responsible for the bulk of the work...the top 10% of the most prolific elite can be credited with 50% of all contributions, whereas the bottom 50% of least productive workers can claim only 15%...the most productive contributor is about 100 times more prolific than the least.