Table:
|  |  | 30 June 2019 | 30 June 2018 |
| --- | --- | --- | --- |
|  | Note | $'000 | $'000 |
| CURRENT |  |  |  |
| Prepayments |  | 2,631 | 3,827 |
| Capitalised transaction costs |  | 1,496 | - |
| Security deposits | 6(a) | 8,822 | 4,151 |
| Customer incentives | 6(b) | 625 | 764 |
| Other current assets |  | 412 | 412 |
| Contract costs 6(c) | 6(c) | 446 | - |
| Total other assets - current |  | 14,432 | 9,154 |
Paragraphs:
6 Other assets (continued)
(a) Security deposits
Included in the security deposits was $8.8 million (2018: $4.2 million) relating to deposits held as security for bank guarantees.
(b) Customer incentives
Where customers are offered incentives in the form of free or discounted periods, the dollar value of the incentive is capitalised and amortised on a straight-line basis over the expected life of the contract.
(c) Contract Costs
From 1 July 2018, eligible costs that are expected to be recovered will be capitalised as a contract cost and amortised over the expected customer life.
Question:
How was contract costs amortised?
Answer: over the expected customer life