Table schema:
CREATE TABLE table_171748_3 (change_over_same_quarter_the_previous_year VARCHAR, _percentage_trains_arriving_within_5_mins_of_scheduled_time__over_three_months_ VARCHAR)

Question: What's the change over same quarter the previous year in the period when the 89.6% of the trains arrive within 5 minutes of scheduled time (over three months)?
SQL: SELECT change_over_same_quarter_the_previous_year FROM table_171748_3 WHERE _percentage_trains_arriving_within_5_mins_of_scheduled_time__over_three_months_ = "89.6%"