largest operators of open-loop and closed-loop retail electronic payments networks the largest operators of open-loop and closed-loop retail electronic payments networks are visa , mastercard , american express , discover , jcb and diners club . with the exception of discover , which primarily operates in the united states , all of the other network operators can be considered multi- national or global providers of payments network services . based on payments volume , total volume , number of transactions and number of cards in circulation , visa is the largest retail electronic payments network in the world . the following chart compares our network with those of our major competitors for calendar year 2007 : company payments volume volume transactions cards ( billions ) ( billions ) ( billions ) ( millions ) visa inc. ( 1 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 2457 $ 3822 50.3 1592 .

payments volume ( billions ): visa inc. ( 1 ): 2457
mastercard: 1697
american express: 637
discover: 102
jcb: 55
diners club: 29
total volume ( billions ): visa inc. ( 1 ): 3822
mastercard: 2276
american express: 647
discover: 119
jcb: 61
diners club: 30
total transactions ( billions ): visa inc. ( 1 ): 50.3
mastercard: 27
american express: 5
discover: 1.6
jcb: 0.6
diners club: 0.2
cards ( millions ): visa inc. ( 1 ): 1592
mastercard: 916
american express: 86
discover: 57
jcb: 58
diners club: 7

( 1 ) visa inc . figures as reported previously in our filings . source : the nilson report , issue 902 ( may 2008 ) and issue 903 ( may 2008 ) . note : visa inc . figures exclude visa europe . figures for competitors include their respective european operations . visa figures include visa , visa electron , and interlink brands . visa cards include plus proprietary cards , but proprietary plus cash volume is not included . domestic china figures are excluded . mastercard figures include pin-based debit card figures on mastercard cards , but not maestro or cirrus figures . china commercial funds transfers are excluded . american express and discover include business from third-party issuers . jcb figures are for april 2006 through march 2007 , but cards and outlets are as of september 2007 . jcb total transaction figures are estimates . our primary operations we generate revenue from the transaction processing services we offer to our customers . our customers deliver visa products and payment services to consumers and merchants based on the product platforms we define and manage . payments network management is a core part of our operations , as it ensures that our payments system provides a safe , efficient , consistent , and interoperable service to cardholders , merchants , and financial institutions worldwide . transaction processing services core processing services our core processing services involve the routing of payment information and related data to facilitate the authorization , clearing and settlement of transactions between visa issuers , which are the financial institutions that issue visa cards to cardholders , and acquirers , which are the financial institutions that offer visa network connectivity and payments acceptance services to merchants . in addition , we offer a range of value-added processing services to support our customers 2019 visa programs and to promote the growth and security of the visa payments network . authorization is the process of approving or declining a transaction before a purchase is finalized or cash is disbursed . clearing is the process of delivering final transaction data from an acquirer to an issuer for posting to the cardholder 2019s account , the calculation of certain fees and charges that apply to the issuer and acquirer involved in the transaction , and the conversion of transaction amounts to the .

Questions:
what was the total payment volume for american express, in billions?
and what was the average volume per transaction?
and what was this average volume for the jcb, also in billions?

Answers:
637
127.40
91.67