I apologize for the erroneous numbers I posted above. Below is a more concise table for a double deck showing correct values for 70%, 80%, 90%, 95%, and 99% coverage using the most likely deck compositions, specifically at the penetration indicated.

Code:
            # of possible
                deck              70%         80%         90%         95%         99%
  Pen.       compositions    coverage    coverage    coverage    coverage    coverage
 -----       ------------   ---------   ---------   ---------   ---------   ---------
    15          1,262,459        3.9%        5.9%        9.9%       14.4%       26.4%
    16          1,940,015        3.4%        5.2%        8.7%       12.8%       23.8%
    17          2,905,760        2.9%        4.5%        7.7%       11.4%       21.5%
    18          4,249,281        2.5%        4.0%        6.9%       10.3%       19.6%
    19          6,075,858        2.2%        3.5%        6.2%        9.3%       17.9%
    20          8,505,345        2.0%        3.1%        5.6%        8.5%       16.4%
    21         11,669,700        1.7%        2.8%        5.0%        7.7%       15.2%
    22         15,709,035        1.5%        2.5%        4.6%        7.1%       14.1%
    23         20,766,162        1.4%        2.3%        4.2%        6.5%       13.1%
    24         26,979,744        1.2%        2.1%        3.8%        6.0%       12.3%
    25         34,476,321        1.1%        1.9%        3.5%        5.6%       11.6%
    26         43,361,670        1.0%        1.7%        3.3%        5.2%       10.9%
    27         53,712,091        0.9%        1.6%        3.0%        4.9%       10.4%
    28         65,566,288        0.9%        1.5%        2.8%        4.6%       10.0%
    29         78,918,535        0.8%        1.4%        2.7%        4.4%        9.6%
    30         93,713,782        0.7%        1.3%        2.5%        4.2%        9.2%
    31        109,845,265        0.7%        1.2%        2.4%        4.0%        8.9%
    32        127,155,037        0.7%        1.2%        2.3%        3.8%        8.7%
    33        145,437,633        0.6%        1.1%        2.2%        3.7%        8.5%
    34        164,446,821        0.6%        1.1%        2.1%        3.6%        8.4%
    35        183,905,073        0.6%        1.0%        2.1%        3.5%        8.2%
    36        203,515,141        0.6%        1.0%        2.0%        3.4%        8.1%
    37        222,972,943        0.5%        1.0%        2.0%        3.4%        8.1%
    38        241,980,853        0.5%        0.9%        1.9%        3.3%        8.0%
    39        260,260,447        0.5%        0.9%        1.9%        3.3%        8.0%
    40        277,563,784        0.5%        0.9%        1.9%        3.3%        8.0%
    41        293,682,397        0.5%        0.9%        1.9%        3.3%        8.1%
    42        308,453,343        0.5%        0.9%        1.9%        3.2%        8.1%
    43        321,761,913        0.5%        0.9%        1.9%        3.2%        8.2%
    44        333,540,933        0.5%        0.9%        1.8%        3.3%        8.2%
    45        343,766,869        0.5%        0.9%        1.8%        3.3%        8.3%
    46        352,453,183        0.5%        0.9%        1.8%        3.3%        8.4%
    47        359,641,573        0.5%        0.9%        1.8%        3.3%        8.4%
    48        365,391,868        0.5%        0.9%        1.9%        3.3%        8.5%
    49        369,771,439        0.5%        0.9%        1.9%        3.3%        8.5%
    50        372,845,029        0.5%        0.9%        1.9%        3.3%        8.6%
    51        374,665,863        0.5%        0.9%        1.9%        3.3%        8.6%
    52        375,268,773        0.5%        0.9%        1.9%        3.3%        8.6%
    53        374,665,863        0.5%        0.9%        1.9%        3.3%        8.6%
    54        372,845,029        0.5%        0.9%        1.9%        3.3%        8.6%
    55        369,771,439        0.5%        0.9%        1.9%        3.3%        8.5%
    56        365,391,868        0.5%        0.9%        1.9%        3.3%        8.5%
    57        359,641,573        0.5%        0.9%        1.8%        3.3%        8.4%
    58        352,453,183        0.5%        0.9%        1.8%        3.3%        8.4%
    59        343,766,869        0.5%        0.9%        1.8%        3.3%        8.3%
    60        333,540,933        0.5%        0.9%        1.8%        3.3%        8.2%
    61        321,761,913        0.5%        0.9%        1.9%        3.2%        8.2%
    62        308,453,343        0.5%        0.9%        1.9%        3.2%        8.1%
    63        293,682,397        0.5%        0.9%        1.9%        3.3%        8.1%
    64        277,563,784        0.5%        0.9%        1.9%        3.3%        8.0%
    65        260,260,447        0.5%        0.9%        1.9%        3.3%        8.0%
    66        241,980,853        0.5%        0.9%        1.9%        3.3%        8.0%
    67        222,972,943        0.5%        1.0%        2.0%        3.4%        8.1%
    68        203,515,141        0.6%        1.0%        2.0%        3.4%        8.1%
    69        183,905,073        0.6%        1.0%        2.1%        3.5%        8.2%
    70        164,446,821        0.6%        1.1%        2.1%        3.6%        8.4%
    71        145,437,633        0.6%        1.1%        2.2%        3.7%        8.5%
    72        127,155,037        0.7%        1.2%        2.3%        3.8%        8.7%
    73        109,845,265        0.7%        1.2%        2.4%        4.0%        8.9%
    74         93,713,782        0.7%        1.3%        2.5%        4.2%        9.2%
    75         78,918,535        0.8%        1.4%        2.7%        4.4%        9.6%