What might account for the dramatic increase in presidential pardons issued by president obama in 2016 and 2017

President Obama has claimed that his use of pardon has been motivated by a belief that the sentencing system in the United States imposes excessively long period of time for minor crimes (in particular drug related), and was especially biased against minorities.

He began a program called Clemency Initiative, which encouraged qualified federal inmates to apply to have their sentences commuted. This caused a surge in requests. Obama granted clemency to more people convicted of federal crimes that any chief executive in 64 years. But he also received far more requests than any president on record due to this program.

a drastic rise in oil prices ended decades of postwar.