In aggregate, only roughly 50% of gaps are filled. Statistics:...

In aggregate, only roughly 50% of gaps are filled.

Statistics: Gap Threshold of 0,1%
When running the tests, we get the following statistics for bearish and bullish gaps. Percentages refer to the fill-rate. For instance, 20% means that 20% of all gaps were filled.
Bullish Gaps: 59% (2155 instances
Bearish Gaps: 61% (1809 instances)
As you see there really is not a big difference between the two.

Statistics: Gap Threshold of 0,5%
Here we look at gaps that are at least 0,5%.
Bullish Gaps: 43% (702 instances)
Bearish Gaps: 42% (650 instances)

Statistics: Gap Threshold of 1%
And finally, we take a look at larger gaps of 1% or more.
Bullish Gaps: 28% (204 instances)
Bearish Gaps: 33% (202 cases)

As you can see, having a rhetoric of "All gaps are filled" is an erroneous assumption.