Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_90 (gdp_per_capita__us$_ VARCHAR, gdp__billion_us$_ VARCHAR)
### Question:
What is the per-capita GDP for the country with an overall GDP of 156.640?
### Answer:
SELECT gdp_per_capita__us$_ FROM table_name_90 WHERE gdp__billion_us$_ = "156.640"