The proportion of nuisance calls about payment protection insurance (PPI) has tumbled over the past year.
It now accounts for 13% of all nuisance calls where a subject could be identified, down from 22% in 2013, according to Ofcom.
That said, PPI remains the most common type of unwanted call, with loft insulation close behind. The proportion of those calls rose from 2% in 2013 to 8% this year.
Calls about home improvements in general were up from 3% to 7% and calls about solar panels rose from 2% to 6%.
Ofcom's latest research into nuisance calls also found that the number of people receiving unwanted calls in 2014, and the average number received, was largely flat compared to last year.
In 2014, the average total number of unwanted calls received was 8.7 per person, or around two a week.
The telecoms watchdog also found that the most prevalent types of nuisance calls in 2014 were live marketing calls (38%) with silent calls (37%) following closely behind. Recorded sales calls (12%) took third place.
Most unwanted calls were considered "annoying" (81%) - but this was an improvement compared to 86% in 2013.
There was also a fall in the proportion of calls considered 'distressing' (9% to 6%) and an increase in those not deemed to be a problem (7% to 12%).
Work still to do
Ofcom said it is "making progress in the key areas of enforcement and tracking down companies behind nuisance calls". It is pursuing a number of companies suspected of making silent and abandoned calls.
It said the most recent investigation it has opened concerns Ageas 50 Limited, trading as RIAS and Castle Cover.
Claudio Pollack, Ofcom's consumer group director, said: "While progress is being made, we are under no illusions that there is still more work to do. Together with Government, other regulators, consumer groups and charities, we're exploring all possible ways of better protecting consumers."