This period of major and controversial legislation was also one of memorable exploration successes and field developments. The remarkable volumes of reserves discovered and the large average size of discovery are shown in Appendices 8.1 and 8.2. The number of significant discoveries was also notable (Appendix 8.3), while the exploration success rate (Appendix 8.4) was high by international standards. Expenditures on field developments grew dramatically at this time, and in real terms attained their highest ever levels (Appendix 8.5). Oil production commenced in 1975 but was confidently predicted soon to overtake gas production (Appendix 8.6). These years saw the development of some of the historically most important fields in the history of the province (Appendix 8.7). In many respects this was the most exciting time in the whole history of North Sea oil and gas.