DAX Progress calculation

// Assumptions:
// You have a Dates table in your model that
// stores all days that cover all full years
// that are present in your table. This is
// the calendar in your model (marked as such).
// This calendar must be DISCONNECTED from
// the fact table. Say your fact table is T.
// Apart from the Document field in T all the
// other fields should be hidden. You should not
// slice by them.

// The measure will tell you what the percentage
// of work has been completed until the last
// day visible in the current context. This
// measure works for any selection of documents
// and is relative to this selection.

[Progress] =
var __lastVisibleDate = MAX( Dates[Date] )
var __documentsWithLastDates =
    GENERATE(
        SELECTCOLUMNS(
            VALUES( T[Document] ),
            "@Document", T[Document]
        ),
        // For each document and the last
        // visible date we have to get the
        // latest row in T.
        topn(1,
            CALCULATETABLE(
                T,
                T[Date] <= __lastVisibleDate
            ),
            T[Date],
            DESC
        )
    )
var __totalProgress =
    DIVIDE(
        SUMX(
            __documentsWithLastDates,
            T[Proportion] * T[Progress Target]
        ),
        SUMX(
            __documentsWithLastDates,
            T[Proportion]
        )
    )
RETURN
    __totalProgress