A 1994 study of key pathogens associated with CAP in the US reported that 34% of these infections were caused by Streptococcus pneumoniae, 15% Haemophilus influenzae and Moraxella catarrhalis, 10% Mycoplasma pneumoniae, 7% Legionella spp. and a mixture of other pathogens. European etiological data compiled from 26 prospective studies from 10 European countries confirmed that S. pneumoniae was the most common CAP pathogen, reported in more than 25% of cases. Chlamydia pneumoniae was identified in approximately 12.5%, followed by just under 10% of Mycoplasma pneumoniae and viral infections. Legionella was identified in 5% of cases and the incidence of H. influenzae was only about 4%