2001 Australian Two Dollar Varieties
The Ian Rank-Broadley portrait of Queen Elizabeth II underwent multiple small changes in the course of its use from 1999 to 2019, but especially so in the period just after its introduction. In 2001 on some denominations the designer's initials IRB under the Queen's neck changed from a sans serif font to a serif font. The 2001 $2 was one of the affected denominations, with the first coins being struck with the designer's initials being in a sans serif font and spaced out, and the remaining coins being struck with the designer's initials R and B being joined at the base and all in a serif font.
The small change was likely done to improve die life, and the initial IRB spaced design is less common in circulation, though neither variety is rare. The IRB spaced variety accounts for approximately 19% of circulating coins and the IRB joined variety accounts for approximately 81% of circulating coins.