From the Summary: "The program activities of most federal agencies are generally funded on an annual basis through the enactment of 'regular appropriations acts'. When those annual appropriations acts are not enacted by the beginning of the fiscal year (i.e., by October 1), one or more continuing appropriations acts (commonly known as 'continuing resolutions' or CRs) may be enacted to provide temporary funding to continue certain programs and activities until action on the regular appropriations acts is completed. [...] This report provides detailed information on CRs beginning with FY1977, which was the first fiscal year that began on October 1. Congress has enacted one or more CRs in all but three of the last 44 fiscal years (FY1977- FY2020). In addition, in 11 of the last 19 fiscal years, the initial CR--and in some years subsequent CRs-- provided continuing appropriations for all the regular appropriations acts."
CRS Report for Congress, R46595
Congressional Research Service: https://crsreports.congress.gov/