Between 1900 and 2006 , total world steel production : increased decreased

I think it has increased.

The answer is: increased

Since the 1900's World crude steel production has increased and will continue to grow, as China and India are accounting for more than half of its yearly production. The only period of recession can be seen in the image below in 1970, a recession came as a result of stagnating demand for steel products in global markets

but starting this century, the tendency kept growing. In 2017 estimates for the year record 1,691.2 million tonnes.

Ever since then, the steel production has doubled since the mid-1990s

the industry has found new opportunities to restructure and add investments in new technologies.

See below:

an unexpected salary cut

the answer to your question is:

strong-mayor system