Peter Da Costa, chief executive of the firm which markets and services the 6-seater Mercedes Vito taxi, told Reuters the effect on business for cab drivers from the airport shutdowns caused by the ash cloud was "horrendous.""It sent jitters right the way through the cab trade and everybody got spooked because they were saying this volcano could go on for months," he said after Eco City reported a 30 percent increase in revenues for 2009.Eco City said although trading conditions remained challenging, it was cautiously optimistic."People are returning back to cabs now thanks to the bankers' bonuses, so if the driver can see steady income it settles it all down," Da Costa added.He said the company's share of the market, in which it competes with Manganese Bronze, was running at about 24 percent, adding Eco City had now sold more than 700 of the Vito taxis since they were launched in mid-2008.He said the group had increased production at its Coventry site, where it kits out the basic vehicle model sent across by Mercedes from Spain, to 12 units per week from 8.That stands in contrast to Manganese Bronze, the maker of the traditional TX4 black cab, which is moving production to China to save costs.For 2009, Eco City narrowed its pretax loss to 0.2 million pounds ($294,800) from 0.7 million as sales of higher margin new Vitos tripled to 398 units during the year.Eco City's shares were up 7.5 percent at 5.4 pence at 0845 GMT.