The Value of a "Valued" Employee

If I didn't love my job I wouldn't be starting my 12th year at the same place.  I even took a cut in pay because my last job was so AWFUL I had to move on regardless of salary.  That being said...I have to wonder how much my dedication, contributions and hard work are really appreciated and respected.  Ultimately, the paycheck should be a reflection of that.  I was doing some quick figuring in my head and came to the realization that in 12 years my salary has jumped by an average of .66 per hour per year.  WOW that is more than a little disheartening since I have had about 4 or more promotions during that time and my annual reviews are always rated at the highest levels. 
My son and I started new jobs on the same day in the same year...his salary has increased by an average of $2.00 per year. We are not in the same field but, .66 certainly doesn't seem to match what I am being told my value to the department is.  My daughter is in a similar field that I am in, has increased her salary by a whopping 50K per year.  This salary disparity makes me wonder what I am doing wrong! It has to be because I am not pushy enough about it.  Either I have over-estimated my value or the corporate powers that be have under-estimated it...I am not sure which way it is.  I am always being told how hard it would be on everyone if I were to leave...but apparently not.  There are people 1 and 2 position titles below me making nearly the same salary or more than I make.  How do I know this when we are not supposed to discuss salary (for obvious reasons)  I hear people talk, I pay attention.  What does that tell me...someone is blowing smoke up my ass!  Oh I know I have skills, unique skills but they are apparently taken for granted and not as valued as they should be and it is my own fault because I do not let it be known that I know!  Since they are my skills I apparently take them for granted too.  Time to look at the market for my skills?  As I said previously I love my job...but it is getting more and more difficult to make ends meet.