Adjusting development for temperature

Given that the basement is still coolish from the winter, what would
be the best development time factor for D76 at 60 deg F (15 deg C)?

An experiment with a roll of film at 1.66x recommended time yielded a
rather razor thin negative, though the film had been sitting in the
camera a year or so.  This time factor was taken from an old Manual of
Photography by Focal Press, but it was not specific to D76, just part
of a table of suggested factors at a given "temperature coefficient".
The Manual refers to temperature coefficient for developing agents and
listed a table of factors for a coefficient of 2.75. Here is a part of
the table:

Temp:         Factor
15 deg C:  1.66
17 deg C:  1.35
20 deg C:  1.00
22 deg C:  0.82

I am just getting back into B&W film again, after a long hiatus.  Any
comments on an appropriate development time for the next roll?

Some further searching on Google found the following link with some
more details:

"A characteristic, named the "temperature coefficient," has been used
as the quantitative measure of the change of activity. This is defined
as the ratio of
the development times required to produce equal density at two
temperatures differing
by 10=B0C., which is, of course, a difference of 18=B0F. The values
obtained range from 1.3 for metol alone, through 1.9 for pyro and
metol-hydroquinone combinations, to 2.5 for glycine."
  from: http://www.questia.com/PM.qst?a=3Do&d=3D97634617
  (in referernce to the book: Handbook of Photography by Keith Henney,
Beverly Dudley; Whittlesey House, 1939.)

Thanks for any comments.