Here's the AP World score overview for the 2018 exam from Trevor Packer. Almost 9% earned a 5, almost 20% earned 4's, and the number of 3's and 2's were similar at about 27%. And 15% earned only 1 point.
You can see how students did on different components of the exam in the tweets below.
On the multiple choice, Packer notes that students did better on Period 4 than on period 3. Packer initially announced that he would split the course in 2019 and begin with period 4.