My last visit was in 2002.Immigration was no different.Still look through every passport.If your one of the first of the plane then no problem but if not, join the lines!
New were body scanners and hand luggage checks at the top of the little escalator just after you've handed your cases back after picking them up off of the carousel.Long lines which moved slowly.
Two years on they may have improved the system perhaps a more recent flyer will let us know.An average time well I suppose that depends on how near the front of the immigration line you are and how quick your luggage comes round.......