- Economic diffusion index fell below 50 for the first time in six months - (Companies researched: 23, 118 ; Valid responses: 9,924 ; Response rate: 42.9 %; Survey start date: May 2002) Overview of April 2018 Economy continues at a standstill The economic diffusion index (DI) in April 2018 was 49.8, down 0.6 points from the previous month, and worsened for the first time in two months. The domestic economy remains at a standstill, with the DI falling below 50 due to decrease