May 6 (Reuters) - U.S. energy firms likely added a near-normal 74 billion cubic feet (bcf) of natural gas into storage last week, according to the average estimate in a Reuters poll released on Wednesday.

The estimate compares with an injection of 104 bcf during the same week a year ago and an average increase of 77 bcf over the past five years (2021-2025) for the week.

In the prior week ended April 24, energy firms added 79 bcf of gas into storage. USOILN=ECI

If correct, the forecast for the week ended May 1 would increase stockpiles to 2.216 trillion cubic feet. That figure would be about 4% above the level of the same week a year ago and about 7.3% above the five-year average for the week.

The U.S. Energy Information Administration is scheduled to release its weekly storage report at 10:30 a.m. EDT (1430 GMT) on Thursday.

There were 81 total degree days (TDDs) last week, above the 30-year normal of 70 TDDs for the period, data from financial firm LSEG showed.

Total degree days measure the number of degrees a day's average temperature is above or below 65 degrees Fahrenheit (18 degrees Celsius) to estimate demand to cool or heat homes and businesses.

Reuters polled 12 analysts, whose estimates ranged from injections of 63 bcf to 84 bcf, with a median increase of 74 bcf.

Early estimates for the week ending May 8 ranged from injections of 64 bcf to 114 bcf, with an average increase of 79 bcf.

Those figures compare with an injection of 109 bcf during the same week last year and a five-year average increase of 84 bcf.

Following is a list of poll participants. All figures are in billion cubic feet: