A new teaching method to teach vocabulary to sixth-graders involved having students work in groups on an assignment to learn new words. After the lesson was completed, the students were tested at \( 1 \) -month intervals. The average score for the class \( S ( t ) \) can be modeled by.
\(S ( t ) = 94 - 18 \ln ( t + 1 )\), where \( t \) is the time in months after completing the assignment. If the average score is \( 69 \) , how many months have passed since the students completed the assignment? Round to the nearest month.
\(\square\) month(s) have passed since the students completed the assignment.