guarantees and warranties in april 2015 , we entered into joint venture arrangements in saudi arabia .
an equity bridge loan has been provided to the joint venture until 2020 to fund equity commitments , and we guaranteed the repayment of our 25% ( 25 % ) share of this loan .
our venture partner guaranteed repayment of their share .
our maximum exposure under the guarantee is approximately $ 100 .
as of 30 september 2015 , we recorded a noncurrent liability of $ 67.5 for our obligation to make future equity contributions based on the equity bridge loan .
air products has also entered into a sale of equipment contract with the joint venture to engineer , procure , and construct the industrial gas facilities that will supply gases to saudi aramco .
we will provide bank guarantees to the joint venture of up to $ 326 to support our performance under the contract .
we are party to an equity support agreement and operations guarantee related to an air separation facility constructed in trinidad for a venture in which we own 50% ( 50 % ) .
at 30 september 2015 , maximum potential payments under joint and several guarantees were $ 30.0 .
exposures under the guarantee decline over time and will be completely extinguished by 2024 .
during the first quarter of 2014 , we sold the remaining portion of our homecare business and entered into an operations guarantee related to obligations under certain homecare contracts assigned in connection with the transaction .
our maximum potential payment under the guarantee is a320 million ( approximately $ 30 at 30 september 2015 ) , and our exposure will be extinguished by 2020 .
to date , no equity contributions or payments have been made since the inception of these guarantees .
the fair value of the above guarantees is not material .
we , in the normal course of business operations , have issued product warranties related to equipment sales .
also , contracts often contain standard terms and conditions which typically include a warranty and indemnification to the buyer that the goods and services purchased do not infringe on third-party intellectual property rights .
the provision for estimated future costs relating to warranties is not material to the consolidated financial statements .
we do not expect that any sum we may have to pay in connection with guarantees and warranties will have a material adverse effect on our consolidated financial condition , liquidity , or results of operations .
unconditional purchase obligations we are obligated to make future payments under unconditional purchase obligations as summarized below: .

2016
$917
2017
117
2018
63
2019
55
2020
54
Thereafter
164
Total
$1,370

approximately $ 390 of our long-term unconditional purchase obligations relate to feedstock supply for numerous hyco ( hydrogen , carbon monoxide , and syngas ) facilities .
the price of feedstock supply is principally related to the price of natural gas .
however , long-term take-or-pay sales contracts to hyco customers are generally matched to the term of the feedstock supply obligations and provide recovery of price increases in the feedstock supply .
due to the matching of most long-term feedstock supply obligations to customer sales contracts , we do not believe these purchase obligations would have a material effect on our financial condition or results of operations .
the unconditional purchase obligations also include other product supply and purchase commitments and electric power and natural gas supply purchase obligations , which are primarily pass-through contracts with our customers .
purchase commitments to spend approximately $ 540 for additional plant and equipment are included in the unconditional purchase obligations in 2016. .

Question: Analyse this data from a financial earnings document. what was the decrease observed in the unconditional purchase obligations during 2016 and 2017?
Choices:
-0.00087
-6.83761
-0.94547
0.10033
-0.87241
Correct choice index: 4