code: function formatYear (date, format, delimiter, reverse) {
    var range = this.getRange(date || new Date(), 'year');
    format = format || DEFAULT_FY_FORMAT;
    delimiter = delimiter || DEFAULT_DELIMITER;
  
    var opIdx = format.indexOf('>>');
    var options;
    if (0 < opIdx) {
      options = format.slice(opIdx);
      format = format.slice(0, opIdx);
    } else {
      options = '';
    }
    var splited = delimiter ? format.split(delimiter) : [format];
    if (splited.length === 1) {
      return this.format(reverse ? range.to : range.from, format + options);
    } else if (reverse) {
      return this.format(range.to  , splited[0] + options) + delimiter +
             this.format(range.from, splited[1] + options);
    } else {
      return this.format(range.from, splited[0] + options) + delimiter +
             this.format(range.to  , splited[1] + options);
    }
  }
docs: 年度を表す表記を返します
  @method formatYear
  @param  {DATE}      date       含まれる日時           既定値 new Date()
  @param  {String}    format     フォーマット           既定値 'Y/M - Y/M'
  @param  {String}    delimiter  開始と終了を分ける文字 既定値 '-'
  @param  {Boolean}   reverse    結合順を逆にする       既定値 false
  @return {String}    formatted