Global Office Rents: Dublin has fallen from the 10th most expensive location in the world  for prime office rents in 2008, to a 17th ranking in 2009, after a 28% annual dip. London’s West End is again the world’s most expensive office market, according to CB Richard Ellis Group, Inc. (CBRE) Global Research and Consulting’s semi-annual Global Office Rents survey, which was published on Tuesday. Tokyo’s Inner Central has slipped to second place, followed by that city’s Outer Central market. Hong Kong’s Central Business District (CBD) and Moscow are fourth and fifth respectively in the CBRE report, which tracks office occupancy costs in nearly 180 cities around the globe.