When there is an increase in a person's income, for example due to a wage rise, a good for which the demand rises due to the wage increase, is referred as a normal good.
On the other hand, with inferior or normal goods, people spend a lesser proportion of their income.
This depends on a lot of factors such as geographical locations, socio economic conditions in a country, local traditions and many more.
The demand for normal goods are determined by many types of consumer behaviour.
Economic theory assumes that a good always provides marginal utility (holding everything else equal).
A caveat to the table above is that not all goods are strictly normal or inferior across all income levels.
Another potential caveat is brought up by "The Notion of Inferior Good in the Public Economy" by Professor Jurion of University of Liège (published 1978).
Consumption of many public goods will decrease when a rational consumer's income rises, due to replacement by private goods, e.g. building a private garden to replace use of public parks.
But when effective congestion costs to a consumer rises with the consumer's income, even a normal good with a low income elasticity of demand (independent of the congestion costs associated with the non-excludable nature of the good) will exhibit the same effect.
This makes it difficult to distinguish inferior public goods from normal ones.