For a member employed and participating in the retirement system prior to January 1, 2003, who has elected not to participate in the cash balance benefit, a member’s share of the fund arising from the compensation deductions made in accordance with section 84-1308 shall be known as his or her employee account. Each year commencing January 1, 1975, and ending December 31, 1984, regular interest shall be credited to the employee account. As of January 1 of each such year, a member’s employee account shall be equal to one hundred percent of his or her employee account as of the next preceding January 1 increased by any regular interest earned and any amounts deducted from the member’s compensation since the next preceding January 1 in accordance with the provisions of section 84-1308. On and after January 1, 1985, the employee account shall be equal to the sum of the stable return account, the equities account, and any assets of additional accounts created by the board pursuant to section 84-1310.01.