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)

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)?
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%"
SELECT "change_over_same_quarter_the_previous_year" FROM "table_171748_3" WHERE "89.6%" = "_percentage_trains_arriving_within_5_mins_of_scheduled_time__over_three_months_"