Digital BW, The Print

I see a lot of paper manufacturers talk about whiteness and opacity 
when describing their papers.  I always think in Lab terms when 
thinking of the brightness and color of the paper (and wish they'd 
provide that data).

For example, the data sheet for Innova Cold Press specifies a whiteness 
of 88.32%.  Is there any correlation between "whiteness" and Lab 
numbers?  Can I determine or estimate the Lab values from their 
whiteness value?

Also, what does the opacity number mean?  The above paper specifies an 
opacity of 98.95%.

Thanks,

Lou