In some instances, we incur third party costs that directly relate to the contract to fulfill the contract obligations. These fulfillment costs are capitalized and amortized consistent with how the related revenue is recognized. Changes in our deferred costs on contracts are as follows for the years ended December 31:

	2019			2018
Balance at beginning of year	$	3,746		$	1,780
Fulfillment costs incurred		30,905			9,076
Amortization of fulfillment costs		(19,685	)		(7,110	)
Balance at end of year	$	14,966		$	3,746

Typically, our mobilization services are paid by the customer at the beginning of the contract while the revenue is recognized as control transfers to the customer, which can result in deferred revenue. Normally all other revenue is billed as work progresses, which generally will not result in significant deferred revenue except in those cases where a large mobilization is required for the contract. Changes in our deferred revenue are as follows for the years ended December 31:

	2019			2018
Balance at beginning of year	$	4,357		$	1,477
Acquired from GEOK		—			2,856
Cash received, excluding amounts recognized as revenue from services		20,334			6,580
Amounts recognized as revenue from services		(15,967	)		(6,556	)
Balance at end of year	$	8,724		$	4,357

The following table disaggregates our revenue from services for the years ended December 31:

	2019						2018
	Land		Marine		Total		Land		Marine		Total
North America	$	126,317	$	—	$	126,317	$	71,326	$	—	$	71,326
South America		5,171		18,546		23,717		22,531		—		22,531
Asia Pacific		3,715		101,485		105,200		4,813		—		4,813
Total	$	135,203	$	120,031	$	255,234	$	98,670	$	—	$	98,670

As of December 31, 2019, we had $203.1 million of remaining performance obligations.

We expect to recognize revenue of approximately 62% of these performance obligations in 2020, 19% in 2021 and the remaining approximately 19% in 2022.