Pretty high. It is a primary source of long-chain hydrocarbons, a primary feedstock for chemistry. Most biologically active chemicals produced by industry rely on oil as the chief starting material.
Though any carbon feedstock can address that. For a materials standpoint, there are substitutes.
Natural gas as feedstock to the Haber-Bosch process and coking coal in steel production, for reducing ore, are both much more formidable. They account for a large fraction the consumption of both (15% in the case of coal), and substitutes are difficult.
The story of where Earth's crustal iron comes from, when, and how, particularly as banded iron formations, is another interesting story.
Natural gas as feedstock to the Haber-Bosch process and coking coal in steel production, for reducing ore, are both much more formidable. They account for a large fraction the consumption of both (15% in the case of coal), and substitutes are difficult.
The story of where Earth's crustal iron comes from, when, and how, particularly as banded iron formations, is another interesting story.
https://ello.co/dredmorbius/post/5l_8MqtVwLLvX_DabPjY-g