What is the average birth rate that has a total fertility rate of na, and a natural growth smaller than 2.5?
CREATE TABLE table_name_14 (
    births__000s_ INTEGER,
    total_fertility_rate VARCHAR,
    natural_growth VARCHAR
)
SELECT AVG(births__000s_) FROM table_name_14 WHERE total_fertility_rate = "na" AND natural_growth < 2.5
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the average birth rate that has a total fertility rate of na, and a natural growth smaller than 2.5? ### Input: CREATE TABLE table_name_14 (
    births__000s_ INTEGER,
    total_fertility_rate VARCHAR,
    natural_growth VARCHAR
) ### Response: SELECT AVG(births__000s_) FROM table_name_14 WHERE total_fertility_rate = "na" AND natural_growth < 2.5