American volunteers served 8.1 billion hours in 2010, valued at an estimated $173 billion, according to research from the Corporation for National and Community Service. Although the volunteer rate showed a slight decrease from 26.8% in 2009 to 26.3% in 2010 (the most recent year for which data is available), volunteers contributed approximately the same amount of hours - 8.1 billion in both years. The proportion of volunteers who serve 100 hours or more increased between 2009 and 2010 from 33.2% to 33.8%, and the median number of hours served per volunteer rose from 50 to 52 per year. The research also showed Gen Xers stepped up their volunteering commitment in 2010, giving more than 2.3 billion hours - an increase of almost 110 million hours since 2009.