Half of the entire freemium mobile game revenue from new players is generated by just 0.22% of them, a report from Swrve has revealed.

The app marketing firm added that 53% of freemium revenue, generated by purchases of in-app items or add-ons, falls within the first week of play, with charts showing a shrinking long tail of revenue as the weeks go by.

"It is imperative to make every effort to put the right experiences and offers in front of players from the very moment they begin play in order to maximize the revenue generated in what can be a very short window," the report said.

Half of players spending money for in-game upgrades made their first purchase within a week, with those starting to pay for the game by week ten accounting for less than 1% of spenders.

Beginning in November 2013, Swrve tracked the habits of players starting a range of games within that month, collating data from millions of users over a three month period.

The freemium games sampled were abandoned by almost half of new players within four sessions, with a fifth playing the game only once.

Readings of who was playing the game after a day, a week and a month showed a steep decline.

A third of people were playing the game the day after they first tried it, with half of that playing a week later and only one in twenty playing one month later.

"These numbers relating to retention (and number of sessions played) suggest that acquisition as a metric is in many cases close to worthless," the report said. "As we tend to spend a significant amount of money in this area, that is not a comforting thought."

Figures were calculated using 24-hour periods instead of calendar dates, to compensate for time zone discrepancies.