First thing to understand is that "tax" is a bit of a misnomer. It's really "tax plus whatever other costs we can manage to unbundle and lay on the passengers." Ryanair has led the way in rebranding this as pure "tax" - in fact the government only gets a relatively small part of it, recent APD increases notwithstanding.
A big chunk of the extra costs is likely to be a fuel surcharge, which varies from carrier to carrier (and LH's is pretty steep IIRC). Some carriers (Ryanair as the prime example) also add on their inflated version of "airport charges", "credit card fees", "wheelchair levy" etc. (on which the airline makes a profit - do a search on previous threads here).
Because so many of these surcharges are carrier-specific it's difficult to provide a general breakdown - but if you make a dummy booking on the carrier's website, quite often - before you actually have to put a credit card number in - there'll be an opportunity to get an itemised breakdown of the different charges.