The National Register of Works (CNO) is a dataset for registering civil construction works administered by the Federal Revenue Service. The work must be registered within 30 days of the start of activities. All civil construction works must be registered, with some exceptions, such as small-value renovations. The parties responsible for the work, total area and dates relating to the construction activities are reported. The CNO was created in 2018 to replace the INSS Specific Register of Works (CEI). Works registered in the CEI are being migrated to the CNO and have the same previous registration.