The informational Project stages form lists all stages completed by a project, including the current status. This allows you to compare the project data at different times. To create project stages, use the Create project stages process.
Use the 'All project stage lines' preset to view all project stages of the selected project, including any underlying project lines. This preset also shows the current project lines; current project lines do not have a project stage code. You can analyze the data on the form even further by using the default functionality on the form, including the Filter option, the Group option, the pivot table, the column functions, and the group functions. You could, for instance, compare the values of the different project stages, to see how they have developed over time.