Surplus shall include:

1. (a) Revenue receipts made available by the lapsing of unencumbered appropriation balances at the beginning of the budget year;
2. (b) Receipts from unanticipated miscellaneous revenues of the preceding fiscal year;
3. (c) Receipts from anticipated miscellaneous revenues of the preceding fiscal year in excess of the estimates in the budget;
4. (d) Receipts during the previous fiscal year from taxes or liens against which a complete reserve has been established.

(Acts 1953, No. 404, p. 472, §5.19.)