About Me: UI/UX Designer, Freelance making web and apps, 110K last year. Before that I was an Art Director at a web agency making 90K for a few years. I live and breath design. I've been doing it since I was 14 building geocities sites, now 31. I usually work 6 days a week. Lot's of late hours (taking a break right now at 12:51am). I live in the city, have a very active social life, a GF, and play vids too so i'm not a downer workaholic. I just don't waste too much time.
About Code: Web designers usually only learn CSS/HTML. I use to code all my own CSS up until SASS came out and then I stopped and focused on UX. Now i'm learning Swift and auto-layout for X-Code so that I can handle my own front end for iPhone apps.
It's important to understand the front end code that provides the structure to your designs. There are guidelines and best practices you must adhere to no matter what you are creating. Understanding the building blocks on which your designs are built is an absolute must. You don't have to know how to do it all, but at least a general understanding of the possibilities and limitations. You should always be learning and improving. My advice is to constantly improve and expand on your skill sets and continuously ask yourself if this is the best work I can do (given the time constraints).
About $$$75K+: But since you are asking about money you should know this. If you have the drive and truly give a shit about what you do, you can make much more than 75K. But if you want to work a 9-5 and leave work and work, you can still make $75ish. It will just take longer to get there, but sooner or later you may no longer be relevant. Do you want to risk that!! haha, just kidding.
Good luck with whatever you are using this info for!