Ayone know the wattage used at a Rock concert?

I just attended a Dave Matthews concert last night at a large outdoor venue (very good show). The sound level was incredible, the bass was chest thumping. I'm wondering what type of amplification is used at something like this, ie, number of amps, type of amps, number of watts, that type of thing. Anyone have any experience with this stuff? I kinda like trivial knowlegde of this sort. Thanks.