From gbianchi's last post (he makes these regularly):
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block# 346488 06/03/2015 num %noOut %dead %of tot %of act diff prev value %noOut %vdead %TotVal diff prev
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= 0 62633417 0.00% 0.00% 93.5626% 125855 0.00000 0.00% 0.00% 0.0000% 0.00000
= 1 satoshi (0.00000001 BTC) 424786 36.84% 8.43% 0.6346% 9.86% 15 0.00425 36.84% 8.43% 0.0000% 0.00000
> 1 satoshi <= 0.001 BTC ( ~1$ ) 1802268 75.19% 14.96% 2.6923% 41.82% 2132 418.44983 69.64% 4.39% 0.0030% 0.34730
> 0.001 BTC <= 0.1 BTC 1374072 68.02% 4.87% 2.0526% 31.89% -3121 28932.13841 71.18% 7.27% 0.2080% -90.78105
> 0.1 BTC <= 1 BTC 393208 69.18% 5.30% 0.5874% 9.12% -108 171729.77427 73.57% 7.08% 1.2346% 7.73250
> 1 BTC <= 5 BTC 156615 68.06% 5.38% 0.2340% 3.63% 244 376669.06388 69.36% 5.75% 2.7080% 280.70164
> 5 BTC <= 10 BTC 45309 70.22% 5.16% 0.0677% 1.05% 106 347625.01943 72.04% 5.23% 2.4992% 825.00472
> 10 BTC <= 25 BTC 35885 68.78% 5.43% 0.0536% 0.83% 19 588449.97580 70.05% 5.65% 4.2306% -2.61582
> 25 BTC <= 50 BTC 52567 90.82% 69.66% 0.0785% 1.22% -7 2412077.44158 92.88% 75.44% 17.3412% -602.56042
> 50 BTC <= 75 BTC 5551 68.15% 12.23% 0.0083% 0.13% 18 331829.18959 67.82% 11.08% 2.3856% 1162.22146
> 75 BTC <= 100 BTC 7461 83.77% 5.31% 0.0111% 0.17% -4 708187.78653 84.72% 5.32% 5.0914% -358.06960
> 100 BTC <= 500 BTC 8551 67.20% 3.67% 0.0128% 0.20% 34 1815418.40323 67.65% 2.76% 13.0516% 10706.88586
> 500 btc <= 1000 BTC 1609 75.82% 0.00% 0.0024% 0.04% -5 1120607.34554 75.88% 0.00% 8.0564% -3944.97798
> 1000 BTC 1476 74.53% 0.00% 0.0022% 0.03% -3 6007584.24205 68.60% 0.00% 43.1904% -4283.87542
Total Actives 4309358 68.39% 10.30% 6.4374% 100.00% -680 13909528.83410 74.31% 14.61% 100.0000% 3700.01320
Total 66942775 4.40% 0.66% 100.0000% 125175 13909528.83410 74.31% 14.61% 100.0000% 3700.01320
Transactions 61630417 93869
num : number of addresses in this range of balance
%noOut : percentage of active addresses WITHOUT out operations
%dead : percentage of active addresses with input and output operations prior to 2012
%of tot : percentage of the TOTAL number addresses
%of act : percentage of the number of addresses with balance > 0 (active)
diff prev: number variation compared to the previous table
%noOut : % value transactions WITHOUT output ( % value of range)
%vdead : % operations value prev 2012 ( % value of range))
%TotVal : % value of this range compared to the total value
diff prev: change in value compared to the previous table
donations : 17ykWbCHG6eMfLt42zCJVw5bZE1YxRMihL
So, there's about 23K addresses with > 50 BTC. You're in rare company.