Key to Time Trends Chart
Top half represents high-income countries. Lower portion shows lower-and middle-countries.
Brackets contain the average prevalence of asthma in the country based on ISAAC Phase One and Phase Three data (1993–2003).
The blue bars indicate the
change in prevalence per year
between Phase One and Three.
Bars going to the right show an increase in prevalence and bars to the left show a decrease.
The length of the bar indicates the magnitude of the change.