These costs were provided for coal and nuclear plants in all editions of Projected Costs in the 1980s, for natural gas (combined-cycle gas turbines - CCGT), coal and nuclear in all editions since 1992, and for onshore wind and ground-mounted solar PV in all editions since 2005. Also, for some newer technologies with relatively steep learning curves, state-of-the-art technology today may have improved by 2010-2015. ( Compare this discussion with those in the 2010 and 2015 editions.