pre_text: The Corporation is also exposed to credit risk in relation to its trade accounts receivable. To mitigate such risk, the Corporation continuously monitors the financial condition of its customers and reviews the credit history or worthiness of each new large customer. The Corporation establishes an allowance for lifetime expected credit losses related to doubtful accounts. The doubtful accounts allowance is calculated on a specific-identification basis for larger customer accounts receivable and on a statistically derived basis for the remainder. Factors such as the current economic conditions, forward-looking macroeconomic data and historical information (number of overdue days of the customer’s balance outstanding as well as the customer’s collection history) are examined. The Corporation believes that its allowance for doubtful accounts is sufficient to cover the related credit risk. The Corporation has credit policies in place and has established various credit controls, including credit checks, deposits on accounts and advance billing, and has also established procedures to suspend the availability of services when customers have fully utilized approved credit limits or have violated existing payment terms. Since the Corporation has a large and diversified clientele dispersed throughout its market areas in Canada and the United States, there is no significant concentration of credit risk. The following table provides further details on trade and other receivables, net of allowance for doubtful accounts:
table: At August 31, 2019 2018
table: (In thousands of Canadian dollars) $ $
table: Trade accounts receivable 74,021 95,541
table: Allowance for doubtful accounts (6,759) (6,497)
table: 67,262 89,044
table: Other accounts receivable 8,390 8,250
table: 75,652 97,294
question: Analyse this data from a financial earnings document. What was the average allowance for doubtful accounts from 2018 to 2019?