To what extent has the Federal Reserve monetized government debt? Plot since 1970 the change from a

Question:

To what extent has the Federal Reserve “monetized” government debt? Plot since 1970 the change from a year ago (measured in billions of dollars) in gross federal debt (FRED code: FYGFD) and the change from a year ago (measured in billions of dollars) in the federal debt held by the Federal Reserve System (FRED code: FDHBFRBN).