Solve the following sql problem:
How many users answered "Yes" to the question "Have you had a mental health disorder in the past?" in 3 consecutive years starting from 2016?

Schema:
SCHEMA:
- Table: Question
  - Column: questiontext
    - Samples: [What is your age?, What is your gender?, What country do you live in?, If you live in the United States, which state or territory do you live..., Are you self-employed? (truncated)]
  - Column: questionid
    - Samples: [1, 2, 3, 4, 5]
- Table: Survey
  - Column: SurveyID
    - Samples: [2014, 2016, 2017, 2018, 2019]
  - Column: Description
    - Samples: [mental health survey for 2014, mental health survey for 2016, mental health survey for 2017, mental health survey for 2018, mental health survey for 2019]
- Table: Answer
  - Column: AnswerText
    - Samples: [37, 44, 32, 31, 31]
  - Column: SurveyID
    - Samples: [2014, 2014, 2014, 2014, 2014]
  - Column: UserID
    - Samples: [1, 2, 3, 4, 5]
  - Column: QuestionID
    - Samples: [1, 1, 1, 1, 1]

SELECT COUNT(T2.UserID) FROM Question AS T1 INNER JOIN Answer AS T2 ON T1.questionid = T2.QuestionID WHERE T2.SurveyID IN (2016, 2017, 2018) AND T1.questiontext LIKE 'Have you had a mental health disorder in the past?' AND T2.AnswerText = 'Yes'