attachment for keeping the context:
It does not seem to be an accident that the worst growth disasters ( ... ) are almost all in sub-Saharan Africa. It does not seem to an accident that those growth stars, the Gang of Four and China (and Japan in earlier decades) are all in East Asia. ( ... )
Another sign that regional growth is an important part of the action is that regions move together from one decade to the next. For example, Latin American nations in the 1980s collectively had a famous "lost decade." A regional credit bubble had burst: global banks had given the region a supply of easy credit at low interest rates in the 1970s, then interest rates went up and credit was cut off in the 1980s.
A sensible principle for attribution for national growth performance is that a nation does not get special recognition if its performance is just at the average. It would be foolish for a nation to claim credit for growth that is the same as the average for its region. If a nation is above (or below) these averages, then we can talk about special recognition for the nation's growth performance.
* * *
This principle further reduces the share of growth variation explained by permanent national differences. Some of the variation in decade growth rates explained by national differences was really explained by regional differences. Recalculating, we now get only a little more than a tenth of the variation in decade growth rates explained by national differences. Regional growth differences explain roughly as much of growth as national growth differences do.
1. "was ... explained": the past tense describing a fact or action already done.
2. "now get" and "explain": present tenses describing permanent truths contained in the fact or action already done.
3. "Regional growth differences explain roughly as much of growth as national growth differences do."
- The part of growth explained by national differences is almost all explained by regional growth differences.