Off the March lows this year. July 2015. 2 years is too short a time to consider this strategy. You should be looking back 20 years. And again, it's not how likely success is...it's how f'ing awful this is if it moves against you. And if you can stand to keep the position open when you're staring down a $5k loss against your $800 credit. And I'm plenty familiar with spreads trades--it's in fact how I know to point out stuff like this.
You really think anyone would hold onto this trade with more than 2k loss? Show us your trades so we can trade against you, lol...
If you are out at 2k loss (which is around 7%, then your probability of success is nowhere near 92%. Your probability to hit the 2k loss during the live of the trade is much higher. With much lower winning ratio, and losers still much bigger than winners, not sure you have an edge. Plus even if you set your stop loss around 2k, if the stock gaps, it might go through your stop loss. Doesn't necessarily mean it's a bad trade, just pointing out some issues you might have during the live of the trade.
You are aware this trade is 100% successful as long as goog does not swing and close 20% from current price in either direction. And if it has not done that in 2+ years, chances are it won't happen in the next 2 months. Study this trade carefully and market sentiment, you might learn something.
Using 12/31 as a date to calculate a $2k stop, you'll hit that about 40% of the time. You should be a bit nicer to those who are offering their kind words of doubt and caution.
I have doubts you guys make money trading. In a way that's good, publish your trades so others can trade against you. If my trade is bad, prove it by trading against me otherwise lol...