Series are zero beginning 1988:Q3. Prior to 1988:Q3, level from MTS, Table 6, schedule B-Securities Issued by Federal Agencies Under Special Financing Authorities, column Account balances, Close of this month, sum of Export-Import Bank of the U.S. and GNMA less unpublished detail on U.S. government investment account holdings of participation certificates. Unadjusted flow is the change in the level; data for the most recent ten years show no significant seasonality.
