Decrease in demand
Fall in consumer income
Fall in price of subsidies
Rise in price of compliments
Negative change in taste or fashion
Increase in supply
Fall in raw material costs
Improvement in labour efficiency
A reduction in the rate of indirect tax
Positive technological advance
Decrease in supply
Increase in raw material costs
Increase in labour costs
Increase in rate of indirect tax
Negative factors
Increase in demand
An increase in consumer income
Rise in price of subsidies
Fall in price of compliments
Positive change in taste or fashion