In most cases it’s debatable if there were any submarines. E.g. professor Anna Christensen who was on the 2001 government commission with access to all information has said that she does not think there is solid proof of a single foreign submarine in Swedish waters between 1981 and 1992 (other than U 137 of course).

In 2001 the anti-militarism in Sweden was peaking so that a government appointed commissioner came to the conclusion that there were no subs(except for the sub that were) is hardly surprising.