Apple was forced to defend itself against patent suits more times than any other American firm last year.

The iPad and iPhone creator was the defendant in 59 patent cases last year in the United States. It was followed by Amazon with 50, AT&T with 45 and Google with 39.

Apple was also among the ten plaintiffs with the most patents asserted , according to a report issued by legal analytics firm Lex Machina.

The firm said: "Large technology companies bore the brunt of patent litigation in 2013, highlighting the complex web of lawsuits that has embroiled the technology industry in recent years."

Silicon Valley has become notorious for litigation between major competitors, with data on patent cases from the last decade showing a steep increase from 2011 onwards. More than 6,000 such cases were filed last year in the US District Courts, nearly 700 more than the previous year.

Lex Machina monthly patent cases US

The largest damages in a single case was from outside the tech sector when $1bn was awarded to Monsanto from DuPont concerning a patent for genetically modified seeds. The average damages awarded across all patent cases rose by a quarter from the previous year.

The average time to trial for a case has varied wildly over the past few years, but mostly remained between 800 and 1,200 days.

By the end of January this year only 322 new patent cases had been filed in the US courts, a sharp drop from the previous year but one that is consistent with the limited number of filings patent courts tend to see early in the year.

Last week Apple and Google agreed to dismiss all litigation that existed between the two firms, including about 20 lawsuits, in the hopes that they can push forward patent reform.