Across the companies surveyed, revenues increased 71%, from US$128 million in 2001 to US$219 million in 2002. Despite an increase in revenue between 2001 and 2002, none of the companies surveyed were profitable, largely due to the high cost of low-volume production and a continual focus on R&D. Losses totaled US$405 million in 2002, up 35% from 2001. R&D expenses account for a major proportion of fuel cell companies operational costs. Overall, R&D spending increased by US$42 million or 19% between 2001 and 2002 and for most companies this spending outweighed revenue. Cash flows for the companies surveyed were negative in 2002 compared to positive in 2001. A major factor in this change was the significant decline in cash flow from financing ? from US$612 million in 2001 from US$159 million in 2002 ? accompanied by an increase in the negative cash flow from operations ? from US$200 million in 2001 to US$338 million in 2002.