Hi,I noticed there are may more STARs in the database than SIDs for most airports?Some of the larger airports have no SIDs at all.I use the Level-D 767 using cycle 0608 now

Your observation is probably correct. The busiest airport in the US is KORD OHara Chicago.. no DPs (except for generic vectors only). I personally think it is because the air traffic controllers don't want to give up the manpower they would save by going to RNP like KDFW KPHX KATL etc... but, that is really just my opinion.

In the UK all major airports have SIDs. UK ATC will not accept a flight plan that doesn't include a SID at airports that have published SIDs.SIDs reflect the Noise Preferential Routings and compliance with them is required up to 4000ft. I know that at Heathrow, aircraft are also expected to remain within a "swathe" that is 3km wide (1.5km either side of the SID). Flights are monitored and any aircraft deviating from the swathe is reported. Also, aircaft that exceed the noise limits are fined: