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_11318462_29 (enrolment VARCHAR, in_competition_since VARCHAR, abbreviation VARCHAR)
### Question:
What is the enrollment of STM which has been in competition since 1990?
### Answer:
SELECT COUNT(enrolment) FROM table_11318462_29 WHERE in_competition_since = 1990 AND abbreviation = "STM"