But contributions to the self-described “world’s largest and most successful annual workplace charity campaign” have been falling steadily since 2009, when it raised $282.6 million. Last year’s total dropped to $193.2 million. Also down is the participation rate among federal workers, from 27 percent in 2009 to 14.1 percent last year. Average per capita giving fell from $69.63 to $48. This year’s drive runs through Dec. 15.