It can be seen that in 2016 the figure was around $ 60 billion and now fallen to around $ 20 billion.
US oil and gas production had been the biggest and fastest but a distorted market followed. The glut led to higher inventories and prices began their slide downwards.
Gauging through capital markets is a healthy practice for the sake of stability of all the hydrocarbons market.
Politicians can be misled in their appreciations when a short term abundance is seen as a permanent national shield.
Strategic planning goes in hand with economic rationale !