I`ve been playin’ a bit with excel and made a nice little chart which illustrates how much money will you have after 100 losing trades with different account risk settings.Here it goes:
[ul]
[li]The initial capital is set to 100$
[/li][li]The X-axis (horizontal) is the trade’s number (from 0 up to 100)
[/li][li]The Y-axis (horizontal) is the capital in $ (from 100 decreasing to ~4$)
[/li][li]The colored lines represent the account risk set
[/li][/ul]
----You know that losing 100 trades in a row has less than 0.1% of happening,but its good to be cautious. 
Although it can be clearly seen that a 3.5% account risk will half your account in ~25 trades which is also highly unlucky (except if you trade berserk) its still good to avoid it.
----Also the account risks above 1.75% (below crimson red line) are too close to eachother so it’s almost like 2% is the magical limit.No wonder that any pro says to you not to risk more than 2%/ trade :57:
----I guess the crimson line aka. 1.75% acc. risk is acceptable, so my recommendation is that is a larger gap between the lower acc %-s below this,my recommendation is that it is good not to trade ,never with a higher acc risk of 1.25% (1% recommended also).
----There is a progressive increasing gap above this,but note that your profit is decreasing too,so a 0.00001% account risk might have a tiny risk,it will not give you good returns.So the optimal i recommend is between 0.5% and 1%.
This is a chart of drawdown,in % rates,same here;the x-axis representing number of trades and the y-axis representing the loss of capital (drawdown).
—You can clearly see that the 0.5% acc risk will only lose you 40% only after 100 losing trades,while a 1% will lose you ~63%,while a 3.5% to 2.25% will lose around the same (so why the heck would you use 2.25 even if it has a loss rate about the same, then with using a 3.5% atleast you win more )
—But who da hell loses 100 trades in a row (maybe you:p jk!),so lets see the 20 losing trades (if you go berserk only) you can clearly see that the 4 lines 1.25 , 1.0 , 0.75 , 0.5 are separated from the bulk and will lose you no more than 25%
—The 1% acc risk will only lose you 20% its a major difference,while a 0.5% will only lose 10%,hmm so why not stick in a 0.5% -> 1.0% account risk zone and bend the odds in your favor 
I hope this post was useful to you and you can understand now the rules of the odds. Good Luck