The fungus is sensitive to temperature and when the air temperature is high, the prevalence of the disease decreases to very low levels.
On the basis of a crude comparison it appears that the prevalence of known opioid use has decreased by up to 400 cases.
The prevalence has decreased in recent years.
If prevalence had decreased by 2% a year since 2000 this figure would have been 1.3 billion in 2010 and 2025.
Among male students in 11th grade, prevalence decreased during 1991--2001 and then increased during 2001--2007.
The prevalence of tuberculosis per 100,000 people has decreased slightly from 51 in 1990 to 48 in 2010.
The prevalence decreases the closer to the Equator.
This is a traditional Japanese living arrangement, though its prevalence has decreased in recent years.
And although prevalence did decrease to 29.9% from 1980 to 1998, it has increased since then and appears to still be increasing.
Nowadays, their use and prevalence has dramatically decreased.