Both at the date of the service of the notice under section 8 of this Act relating to the proceedings for possession and at the date of the hearing—

1. a

   if rent is payable weekly or fortnightly, at least thirteen weeks' rent is unpaid;

2. b

   if rent is payable monthly, at least three months' rent is unpaid;

3. c

   if rent is payable quarterly, at least one quarter’s rent is more than three months in arrears; and

4. d

   if rent is payable yearly, at least three months' rent is more than three months in arrears;

and for the purpose of this ground “rent” means rent lawfully due from the tenant.