End of year close book

At the moment I can see the Expense over time report by month. If I close
the book at the end of year, will I be able to compare expense over time
from this year to next year month by month or will it only show report for
the next year? If I don't close the book by the end of this year, will
expense over time report get bigger and bigger as more years get pile on to
it?

I am trying to keep my file clutter free but also be able to see records
over multiple years to get an assessment on progress.

Thanks.