To expand on turnstep's answer, the only way you'll get the numbers to line up is if you can control the font used to display them. There are two types of fonts -- proportional and non-proportional (or fixed-width). With the former, an i character is much narrower than a w. In a fixed-width font, all characters have the same width.

This is important when writing CGI applications with Perl for one simple reason -- you don't control the font in the browser. That said, using the <PRE> or <CODE> tags will cause web browsers to use a fixed-width font to display the data. Now you know why. (And now you can use formats, if you want!)