The survey conducted in Belgium in 2004 showed that most firms have some power over their prices, rather than being in a perfectly competitive market. They tend to stick to their prices for about 10 months before reviewing them, and 13 months before actually changing them. Firms usually adjust prices based on time, but switch to reacting to specific events when needed. The survey also found evidence of both nominal (like contracts) and real (like costs and mark-ups) rigidities in pricing. Overall, the results suggest that many firms in Belgium do not set their prices optimally.