I think it's useful for a junior engineer to display I have experience in x, y, and z, and this is how I rate my personal proficiency in each. I wouldn't take

I think it's useful for a junior engineer to display I have experience in x, y, and z, and this is how I rate my personal proficiency in each. I wouldn't take a 9/10 to mean I am in the top 10% world wide in this skill, rather it is where I consider myself most proficient. For more senior roles I might see it as a slight red flag to be honest.