In this exercise you need to calculate D14 retention rate for users who signed up on Feb 1, 2018.
The purpose of this exercise is to finish the retention curve query we started in the previous lesson. 
It gives us the number of active users per day. The challenge is to complete the query and calculate retention rate for each day.
Submit only the integer part of the retention rate as the answer. For example, if D14 retention rate is 17.666% submit 17 as the answer.
About SQL Habit
Hi, itâs Anatoli, the author of SQL Habit. 
SQL Habit is a course (or, as some of the students say, âbusiness simulatorâ). Itâs based on a story of a fictional startup called Bindle. Youâll play a role of their Data Analyst 
and solve real-life challenges from Business, Marketing, and Product Management.
SQL Habit course is made of bite-sized lessons and exercises (youâre looking at one atm). They always have a real-life setting and detailed explanations. You can immediately apply everything youâve learned at work. 
