In 2005, the European Commission published a comprehensive study of the value of patents for patent owners as well as for the European economy. The study was in part based on a survey of 20,000 patent owners who applied for EPO patents between 1993 and 1997. The survey was performed in 2003. 9000 patent owners responded. The patent owners were asked how much effort was required to produce their inventions and how much monetary value their patents had been worth. The median effort to create the patentable invention was 1 person-year, with 10% of the patent owners requiring 2 or more person-years. The median value of the patents produced was €300,000, with 10% of patent owners reporting values of €10 million Euros or more.