since three years vs since three years ago

Some examples from the web:

• I haven't done that since three years ago.
• 'Cause ever since last week, ever since three years ago when you left...
• Satisfaction since some three years ago we were the only group here that condemned the flaws in the Marrakesh and GATT agreements.
• I've been getting monthly checks ever since I was three years old.
• I am particularly happy since, three years ago in this Chamber, during a previous term of office, I had the privilege of presenting a report on a new strategy for animal health based on the principle 'better prevention than cure'.
• Since I was three years old I've been in a boarding school, it's normal to be here.
• Shawn, I've been worried about you since you were three years old and started eating your own toenails.
• I've known my Ziva since she was three years old.
• Since we took three years to reach this compromise, I would like to point out that the Council and Commission cooperated particularly effectively here.
• It's been ten years since Three on a match opened.
• And three years since I saw you, Cross.
• It's almost three years since 1942.
• It is now three years since Hungary joined the EU.
• It is nearly three years since we adopted the EU's alcohol strategy.
• It is almost three years since the Commission presented the EU's alcohol strategy.
• It has been over three years since I moved here.
• It's been three years since Tom left Boston.
• It is three years since my father died.
• Three years since you beat us?
• I can't believe it's been three years since Smithers left.

Some examples from the web:

• I haven't done that since three years ago.
• 'Cause ever since last week, ever since three years ago when you left...
• Satisfaction since some three years ago we were the only group here that condemned the flaws in the Marrakesh and GATT agreements.
• I am particularly happy since, three years ago in this Chamber, during a previous term of office, I had the privilege of presenting a report on a new strategy for animal health based on the principle 'better prevention than cure'.
• I haven't been in a real relationship since Jerry left me three years ago.
• Have you received letters from him since he left three years ago?
• The European Union has been at the forefront in efforts to tackle the issue since the first crisis three years ago, but more needs to be done.
• Okay, well, why haven't I heard from him since our dinner three years ago?
• I've been following Shing Since my bad died three years ago.
• Since I first heard your voice three years ago you have been constantly on my mind.
• Since I checked him out of a mental institution three years ago.
• Zina and her 10 year old daughter joined her husband, who had been in the camp since 2000, at Sandholm over three years ago.
• Paul Crewe, serving a three-year sentence, hasn't played since he was banned from the NFL six years ago.
• Our country has been at war since we were first attacked three years ago, and we have lost more than a million of our young men.
• Eben Dooley Jr. inherited the regency square mall three years ago after his father passed and has since nearly run it into the ground.
• As you can see, since launching the first Kiddie Kastle project three years ago we've had nothing but unencumbered profit margins.
• I've been covering this story since I moved to Tokyo three years ago.
• We have been discussing European audit mechanisms and financial legislation ever since the major scandals started in the US some three years ago.
• This project was launched three years ago and since then about 20'000 students have participated in the more than 300 projects launched by x to the power of heart.
• I discovered Ana three years ago in Colombia, and we've been together ever since.