Drew's right about upgrading efficiency. You'll gain back low workers and hire more hi-tech people.
Also, although this may not be an option to you yet because of game level, different corps use more hi-tech, in particular the Hi-tech corps, funnily enough! So go for them or industrial types, dunno, just check before you build. Ideally you would have CEOs build in your country because they normally build higher tech corps (most of the time, not all). But that means low tax rate on your behalf, well worth it, and getting your indexes up for good welfare, and making sure you have enough workers free for them.
Keep an eye on the forums here, people often want to swap their lower workers for some hi-tech workers. And you generally get more low workers than the hi-workers you give away
Just basic pointers there. Sorry if it's a bit long winded.