Yes, it is generally acceptable to use the term "poverty percentages" to refer to the percentages of poor people in a given region. In this context, "percentages" can be used interchangeably with "rates" to describe the proportion of individuals or households living in poverty.
In common usage, "percentage" and "rate" can often be used interchangeably to refer to the proportion or frequency of a particular occurrence. However, there may be subtle differences in meaning depending on the context. For example, "percentage" may be used more commonly in everyday conversation or in contexts that are less technical or formal, while "rate" may be used more commonly in technical or scientific contexts.
In general, it is important to consider the specific context and audience when deciding which term to use, and to ensure that the usage is appropriate and clear.