def simulationTimeLine(simTimeInFs):
    """
    Scales simulation time and returns line including units.
    
    """
    if simTimeInFs > 1.0E27:
        # years
        simTime = "%.3f years" % ((simTimeInFs / 1.0E15) / 31557600.0,)
    
    elif simTimeInFs > 1.0E24:
        # days
        simTime = "%.3f days" % ((simTimeInFs / 1.0E15) / 86400.0,)
    
    elif simTimeInFs > 1.0E21:
        # hours
        simTime = "%.3f hours" % ((simTimeInFs / 1.0E15) / 3600.0,)
    
    elif simTimeInFs > 1.0E18:
        # minutes
        simTime = "%.3f mins" % ((simTimeInFs / 1.0E15) / 60.0,)
    
    elif simTimeInFs > 1.0E15:
        simTime = "%.3f s" % (simTimeInFs / 1.0E15,)
    
    elif simTimeInFs > 1.0E12:
        simTime = "%.3f ms" % (simTimeInFs / 1.0E12,)
    
    elif simTimeInFs > 1.0E9:
        simTime = "%.3f us" % (simTimeInFs / 1.0E9,)
    
    elif simTimeInFs > 1.0E6:
        simTime = "%.3f ns" % (simTimeInFs / 1.0E6,)
    
    elif simTimeInFs > 1.0E3:
        simTime = "%.3f ps" % (simTimeInFs / 1.0E3,)
    
    else:
        simTime = "%.3f fs" % (simTimeInFs,)
    
    return simTime