What led to the increase in steel consumption seen on the graph?

Fossil fuels that became popular depends on steel production.
Fossil fuels that became popular depends on steel production.

Steel consumption increased when more people started to use computers.
Steel consumption increased when more people started to use computers.

More building construction is needed to provide for the needs of people.
More building construction is needed to provide for the needs of people.

More people started mining steel that are sold outside of the country.
More people started mining steel that are sold outside of the country.