Patent documents contain several types of information (e.g. technical class code, title, abstract, claims, etc.) which are useful for classifying patents in particular fields and investigating the emergence and growth patterns of new technologies. The rise in patent applications filed under the Patent Cooperation Treaty (PCT) stabilised at an average rate of 5% in the 2000s. The increase was not evenly distributed across countries or technological fields. Since 2000, patenting in the information and communication technology (ICT) and nanotechnology sectors grew at a similar pace (respectively 3% and 4%), whereas biotechnology patenting showed an inverse trend (–4%).