Table:
December 31,

2019	2018

Trade receivables — billed	$136.6	$136.6

Trade receivables — unbilled	39.8	37.0

Trade receivables	176.4	173.6

Allowance for doubtful accounts	(1.3)	(1.3)

Trade receivables, net	$175.1	$172.3

Answer the following question considering the given table and text, feel free to explain how you reached the answer, then present the result in JSON format {"answer": ["ANSWER"], "scale": "SCALE"} (leave scale empty if none).

Background:
Trade Receivables, Net
The carrying amounts reported in the Consolidated Balance Sheets for Trade receivables, net approximate their fair value because of their short-term nature.
A summary of Trade receivables, net of allowance for doubtful accounts is as follows (in millions):
In addition to the amounts above, we have unbilled receivables that we do not expect to collect within the next year included in Other non-current assets in our Consolidated Balance Sheets. Billings for these receivables are based on contractual terms. Refer to Note 11 — Other Non-Current Assets.

Question: What was the percentage change in the net trade receivables between 2018 and 2019?

((175.1-172.3)/172.3) * 100, therefore {"answer": "1.63", "scale": "percent"}