Three in four hotel enterprises in Greece benefited from the increase in tourism last year, as their financial reports have shown, posting an average rise in revenues of 8.4 percent since 2005, according to Hellastat. In 2004, only half of the enterprises had increased their revenues. At the business level, the improvement in the image of tourism is attributed mainly to the companies managing luxurious hotel units which in recent years have invested considerably in upgrading their services, constructing new hotels and developing alternative forms of tourism. This is obvious from the results of the 44 companies in the sample with revenues of more than 10 million euros in 2006, as the average rise came to 11 percent, far higher than the 8.2 percent rise during the 2004-2006 period. Only three companies showed a decline in turnover in that sample. In operating profits, the biggest companies improved by 12.6 percent in 2006, while the entire sample of 800 companies polled had a 9.7 percent rise. Yet the sector suffers from a high number of loss-making companies (some 47 percent of the sample), although the net pretax profit margin rebounded from minus 0.6 percent in 2005 to plus 1 percent in 2006 for companies with revenues of more than 10 million euros, and from 0.4 percent to 0.9 percent for the entire sample. Hellastat found that the key factor in the improvement of the Greek tourism product was the development of holiday housing, where Greece lags due to its insufficient legal framework. The difficulties in legislative and zoning have made the realization of investments in complex tourism infrastructures particularly difficult. There are, however, at this stage over 20 proposals submitted for the creation of installations to include holiday housing, mainly by foreign groups.