CREATE TABLE table_49638 ("Rank" FLOAT, "1-year peak" TEXT, "5-year peak" TEXT, "10-year peak" TEXT, "15-year peak" TEXT, "20-year peak" TEXT)

What is the 20-year peak with emanuel lasker, 2816 as the 15-year peak?
SELECT "20-year peak" FROM table_49638 WHERE "15-year peak" = 'emanuel lasker, 2816'
SELECT "20-year peak" FROM "table_49638" WHERE "15-year peak" = 'emanuel lasker, 2816'