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Proportion of different HIV-1 subtypes stratified according to year of diagnosis. In 2002, samples were collected only during the last 3 months, and therefore this year was excluded from the analysis. 909 samples were collected in 2003, 1107 in 2004 and 513 in 2005. Significance for increasing or decreasing trends was tested with the Cohran-Armitage test. Significant trends are indicated in the figure with an asterisk. p-values are described in the text.
