def is_utility_vehicle(df):
    """Return if vehicle is a utility vehicle, per NHTSA convention."""
    yr = df['YEAR']
    body = df['BODY_TYP']
    return yr.between(1975, 1981) & (body == 43) | yr.between(1982, 1990
        ) & body.isin([12, 56, 68]) | (1991 <= yr) & body.isin([14, 15, 16, 19]
        )
