But here at least, the amount of people who are either self employed, do free lance on the side, or have some kind of investments, is a pretty damn large portion
But at least with the UK system, the bulk of your tax is already covered. I used to submit a self-assessment return online here as I bought/sold shares and had a second job writing magazine articles. I just had o add the details plus expenses I was claiming to offset these, online and the system works out what you have to pay (and takes into account your existing tax from your primary job). You then have a choice to pay it in a lump sum or change your tax code so you pay it off each month (there must be limits to this, not sure, never used this option). The online system is great, loads of information, a clear step by step process and it does all the calculations for you. You can do it bit by bit and it remembers all your details to date. When you finally submit it you get a downloadable PDF that looks just like the paper version but nicely filled in.