So, assume you have a report of 30,000 records that you want to export in CSV format. From the first page of the report you can export 20,000 records and from the subsequent pages you can export 2000 records only. Now, since every page of a report consists of 2000 records, you would have exported from 10 pages to get 20,000 records. Therefore, to export the remaining 10,000 records you must start export from the 11th page of the report. From here you can export 2000 records (i.e 21,000-23,000) and so on.