If I wanted to make a progress bar with the bar extending every half of a percent, would I have to manually make the progress bar for each, or is there an easier way?
Animations can't really be made in Illustrator, but some simple animations can be made easily in Adobe After Effects; you can import your graphics from illustrator into AE, and you could write a script to set the bar length based on the data that you are using for the progress bar. The AE animation can be exported for a number of different uses, depending on what you plan on using the animation for.
This is the best tutorial that I found for using scripts to animate progress bars, and though it is lengthy I think there are some useful concepts in here.
If you'd like to use a CSS animation to make an animation for a website, this tutorial shows how to make a progress bar and has some good explanations of how everything works.