 Since 1990 the total number of hours flown annually by the GA sector has remained in the range 1 @.@ 25 – 1 @.@ 35 million , the dominant sector being traditional GA flying , which accounts for 0 @.@ 6 million per year . An overall increase in aircraft numbers combined with nil growth in hours flown has brought the annual average utilisation per aircraft down from 157 hours in 1984 to 103 hours in 2002 . The decline in asset utilisation has led to speculation that the economic health of the GA industry is weakening , though the lack of data on profitability makes this difficult to confirm . 
