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_87 (market_value__us INTEGER, rank VARCHAR, revenues__us$_billion_ VARCHAR, company VARCHAR)
### Question:
What is the average market value with a revenue greater than 6.2, a Company of national bank of greece, and a Rank smaller than 1?
### Answer:
SELECT AVG(market_value__us) AS $_billion_ FROM table_name_87 WHERE revenues__us$_billion_ > 6.2 AND company = "national bank of greece" AND rank < 1