Beginning 2004:Q1, level from FR Board, CM, based on data available by subscription from Mergent on long-term municipal bonds outstanding, less municipal securities and loans issued by nonfinancial corporate businesses (FOF series FL103162000) and municipal securities and loans issued by nonprofit organizations (FOF series FL163162003). Unadjusted flow is the change in the level; seasonally adjusted flow is obtained using X-12-ARIMA procedure. Prior to 2004:Q1, unadjusted flow from a proprietary Thomson Reuters' database, long-term municipal securities.