4767e3a6___Documentation__8_4__pg_stats__Description
[Name] most_common_vals [Type] anyarray [Description] 
A list of the most common values in the column. (NULL if no values seem to be more common than any others.) For some datatypes such as tsvector, this is a list of the most common element values rather than values of the type itself.
PostgreSQL: Documentation: 8.4: pg_stats