If I'm not mistaken, return on investment is based on what you...

If I'm not mistaken, return on investment is based on what you get back compared to what you put in. If as you say you inherited the property, then your investment was nil so any return is 100% profit, not .003%.
Over the past 40 years, property has typically doubled every 8 years which is an average 8.75% compound return. On the other hand, shares, while more volatile, have averaged 11.49% over the same time so yes, capital growth on shares is better but then the average punter buys shares without leverage so it is only 1:1 meaning you still only get an 11.49% return. Property is almost always leveraged so you might put in a 20% deposit and finance the rest so you are getting a 43.75% return less mortgage costs. Then consider that your yield on property is typically 4% before tax while shares can pay a dividend of anywhere between 0%-25% as this thread has suggested.
The conclusion is for anyone to say that shares are better or property is better is to not fully understand diversification of investment.
For me, I'm happiest holding both.