the crime and rape statistics in sweden have been on a steady trend upward since the 1940s and it increased slightly more around the 2000s, which was the start of the refugee crCIA essentially. so yes, immigrants have had an effect on the rape statistics but relative to the population increase it's been perfectly normal. the rape statistic would've went up either way if you increased the population
also in sweden if you rape someone 5 times then the national rape count increases 5 times. in the united states, only certain states allow you to be charged multiple times for the same crime. in other states, raping someone 5 times will result in 1 sentence, albeit a long one based on the charge (ie, loveual assault, entry, aggrevated assault, abusive assault, etc)
even if you ignore all the obvious factors in the statistics, you could only pin 15 more rapes a year on the immigrant population, which is a lot but not enough to condemn the 9 million immigrants in sweden, unless you believe that all 8,999,985 immigrants in sweden should be held responsible for the 20 that decided to rape people