There's a lot of considerations, none of which I suspect you need worry about at 700 records per year, especially if there are only 2 fields. You could probably have a million records before things start becoming problematic. Factors which contribute to the db limit of 2Gb are field data types (replication id is the largest), indexes, number of fields, number of tables and other objects, and to a lesser extent, the code project. So 2 tables of 5000 records each would result in a file size that is larger than one table with 10000 similar records - because each table adds its own overhead.
EDIT - I would avoid the comma separated values unless absolutely required and that's rare.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.