This slope is called a "Hockey Stick" is represents exponential growth, which always is unsustainable. This illustrates Boom in an economy. One doubles to 2 doubles to 4 doubles to 16 doubles to 32 doubles to .... until a Bust. This is how a Bust looks:
Data for this chart includes domestic hedge funds and represents the best visual I’ve seen of the credit boom and bust.
Notice the top graph is of gold price Boom. Watch for the Bust.
The second is of Household borrowing. Watch for the Boom.