I don't use Rakudo. But the number of lines hints to me that (maybe) you should start looking into using a database.

You didn't really tell us what you are trying to accomplish (the "big picture"), only that you are working with budget data. I'm assuming here that the general rule of "the data amount will exponentially grow over time" holds true for your project as well. A modern relational database like PostgreSQL, MySQL, Oracle or even (oh god oh god, i don't believe i'm saying this) Microsoft SQL Server (please kill me!) could serve you better in the long run than doing your data crunching/reporting/whatever directly on some CSV file.