1972

    Oct

1973

    May    Jun    Sep

1974

    Mar    May    Jul    Sep

1975

    Mar    May    May2     Jul    Sep

1976

    Jan    Mar     May  Jul

1977

    Jan

    Month unknown early in year

    Month unknown late in year

1978

    Jan    Apr    Oct

1979

    Mar    Jul

Date Unknown (late 1970s)

Notes from the measurer

Survey results

Article with quotes from the designer