def METHOD_NAME(name, add, match):
    """
    Accept a numeric value from the matched events and store a running average
    of the values in the given register. If the specified value is not numeric
    it will be skipped
    USAGE:
    .. code-block:: yaml
        foo:
          reg.mean:
            - add: data_field
            - match: my/custom/event
    """
    ret = {"name": name, "changes": {}, "comment": "", "result": True}
    if name not in __reg__:
        __reg__[name] = {}
        __reg__[name]["val"] = 0
        __reg__[name]["total"] = 0
        __reg__[name]["count"] = 0
    for event in __events__:
        try:
            event_data = event["data"]["data"]
        except KeyError:
            event_data = event["data"]
        if salt.utils.stringutils.expr_match(event["tag"], match):
            if add in event_data:
                try:
                    comp = int(event_data)
                except ValueError:
                    continue
            __reg__[name]["total"] += comp
            __reg__[name]["count"] += 1
            __reg__[name]["val"] = __reg__[name]["total"] / __reg__[name]["count"]
    return ret