Get grouped stats from the PIP API.
numeric: Cumulative welfare values, expressed in shares. Any length. They should be monotonically increasing, and sum to 1.
numeric: Cumulative population values, expressed in shares. Any length. They should be monotonically increasing, and sum to 1.
character: One of "stats", "lorenz", "params".
numeric: Requested mean.
numeric: Poverty line. Required for estimate = "stats".
numeric: Proportion of the population living below the poverty line
character: Lorenz curve methodology. Either "lb" or "lq".
numeric: Number of bins. Required for estimate = "lorenz".
character: API version
character: Response format either of c("rds", "json", "csv")
logical: If TRUE (the default) the response is returned as a
tibble
character: Server. For WB internal use only