Russia 1977, full Year, sorted by Michel, used/CTO

If the total price is up to $15.00, a simple letter up to 20 gr.(approx 60 stamps) $6.50 

If the total price is up to $15.00, a simple letter > 20 gr.(> 70 stamps) $8.00 

total price more than $ 15.00, - registered letter weight <100 gr. $12.00,

registered letter weight >100 gr. = $15.00