If you have multiple connected Amazon Marketplaces connected, and have not yet selected a default marketplace the Home Dashboard will default to "All Marketplaces".
If is is defaulting to "All Marketplaces" the statistics that show up on the dashboard will be a total of all the marketplace that are connected.
However, if there is a specific Marketplace you would rather see account information for you can adjust your Default Marketplace from your Account Settings. To get to your Account Settings, click on your email from the top right corner of the screen and then from the dropdown menu click on Settings. On this page, your third option down will be "Default Marketplace". From the "Default Marketplace" field, toggle to the desired marketplace. Click "Save" to apply any changes made.