def export_agg_losses_ebr(ekey, dstore):
    """
    :param ekey: export key, i.e. a pair (datastore key, fmt)
    :param dstore: datastore object
    """
    if 'ruptures' not in dstore:
        logging.warning('There are no ruptures in the datastore')
        return []
    name, ext = export.keyfunc(ekey)
    agg_losses = dstore['losses_by_event']
    has_rup_data = 'ruptures' in dstore
    extra_list = [('magnitude', F32),
                  ('centroid_lon', F32),
                  ('centroid_lat', F32),
                  ('centroid_depth', F32)] if has_rup_data else []
    oq = dstore['oqparam']
    lti = oq.lti
    dtlist = ([('event_id', U64), ('rup_id', U32), ('year', U32)]
              + extra_list + oq.loss_dt_list())
    elt_dt = numpy.dtype(dtlist)
    elt = numpy.zeros(len(agg_losses), elt_dt)
    writer = writers.CsvWriter(fmt=writers.FIVEDIGITS)
    events = dstore['events'].value
    events_by_rupid = collections.defaultdict(list)
    for event in events:
        rupid = event['eid'] // TWO32
        events_by_rupid[rupid].append(event)
    year_of = year_dict(events['eid'], oq.investigation_time, oq.ses_seed)
    rup_data = {}
    event_by_eid = {}  # eid -> event
    # populate rup_data and event_by_eid
    # TODO: avoid reading the events twice
    for rgetter in getters.gen_rupture_getters(dstore):
        ruptures = rgetter.get_ruptures()
        for ebr in ruptures:
            for event in events_by_rupid[ebr.serial]:
                event_by_eid[event['eid']] = event
        if has_rup_data:
            rup_data.update(get_rup_data(ruptures))
    for r, row in enumerate(agg_losses):
        rec = elt[r]
        event = event_by_eid[row['eid']]
        rec['event_id'] = eid = event['eid']
        rec['year'] = year_of[eid]
        if rup_data:
            rec['rup_id'] = rup_id = event['eid'] // TWO32
            (rec['magnitude'], rec['centroid_lon'], rec['centroid_lat'],
             rec['centroid_depth']) = rup_data[rup_id]
        for lt, i in lti.items():
            rec[lt] = row['loss'][i]
    elt.sort(order=['year', 'event_id'])
    dest = dstore.build_fname('elt', '', 'csv')
    writer.save(elt, dest)
    return writer.getsaved()
:param ekey: export key, i.e. a pair (datastore key, fmt)
    :param dstore: datastore object