Box 2.

Service change classification

  1. For April and September:

    • no change: activity remained within 15% of the baseline level;

    • increase: an increase of >15% from baseline;

    • small drop: a reduction of between 15% and 60% from baseline;

    • large drop: a reduction of >60% from baseline.

  2. Overall classification:

    • no change: no change in both April and September;

    • increase: an increase in either April or September;

    • sustained drop: a small or large drop in April, which has not returned to within 15% of baseline by September 2020;

    • recovery: a small or large drop in April, which returned to within 15% of baseline (‘no change’) by September 2020.