Mobile bill pay usage is growing, with more than six millionAmericans using smartphones to pay bills in the past year,according to Fiserv Inc.'s 2011 Billing Household Survey.

Other lead findings from the third annual online poll was thatnearly 20% of online consumer households change the way they billseach month and that e-billing interest has hit a new high, thecompany said.

“Consumers indicate it is important for billers to providemultiple payment options and many report changing the way they paytheir bills month-to-month due to timing and funds availability,”Fiserv said in a statement about the report.

The most common method of paying bills online is at biller orfinancial institution sites, followed by check and auto debit,Fiserv said. The company said it also found that 30% of onlineconsumers have visited a biller's site using their mobile browserto access a monthly bill, typically phone, cable, credit card andutilities.

The poll also found that 32% of consumers who pay bills at theirbank site already receive e-bills and that 38% percent ofnon-recipients are interested, the highest in the survey's threeyears.

Of the 6 million consumers who said they had paid a bill with a mobile device, more than 40% used a mobilebrowser to pay their bill, while 35% used an app downloaded from abiller or a bank and 17% used text to pay.

Six out of every 10 mobile bill payments were made with somekind of card, either debit, credit or prepaid, Fiserv said.

Fiserv said its annual Billing Household Survey was conducted inMay 2011 by The Marketing Workshop and reflects the responses of2,500 adult consumers who are responsible for paying theirhousehold bills.

The company said results are representative of the United Statesonline population of households, which it said is approximately96.4 million out of the 121 million households in the UnitedStates.