English: Millions of tonnes of coal produced each year between 1913 and 1950. The periods corresponding to the two world wars are highlighted in grey. Data from: Historical coal data: coal production, availability and consumption. UK Government (25 January 2019). Retrieved on 23 April 2020.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.