Top Inventory Changes shows a bar graph that informs you how assets in your inventory have changed since discovery.
For example, how many assets now have comments, are owned, and have been assigned tags.
Ideally, you want the bars in this graph to be on the positive side (e.g., +40, +80). When the bars are light blue and on the negative side (e.g., -40, -80), it is not considered good cyber hygiene, meaning that there are a lot of assets that need your attention and action. These assets have to be assigned owners, be tagged, and have comments in their respective Asset Details page.