and minted in cupro-nickel. The 1988 50 cent was a commemorative piece celebrating the tenth anniversary of independence. Later issues simply depict the national crest. The 50-cent and 1 dollar went to nickel-clad steel in 2008. With a high national inflation rate, the low-value 1 and 2 cent coins fell out of use, with prices rounded off to the nearest 5 cents instead. Second coin series In 2012 new, smaller coins were introduced in denominations 10, 20, and 50 cents in nickel-plated steel and brass 1, and 2 dollar coins. The minting of the older coins had become too costly, with most of them being more expensive to produce than they were worth. Like the previous issue, these coins were minted by the Royal Australian Mint. The 2 dollar coin replaced the banknote while the 1, 2, and 5 cent coins were discontinued for having face value too low for production or practical use. Most notably, the 1 and 2 dollar coins have a close similarity to the 1 and 2 dollar coins of Australia being of nearly the same thickness, color, and circumference. The interrupted reeding on the edges are also identical to that of their Australian counterparts, however the metallurgical compositions and weights are slightly different and respective denominations are on the opposite sizes. All the coins of Solomon Islands currently bear the portrait of the country's former head of state, Elizabeth II, Queen of Solomon Islands. Banknotes On 24 October 1977 banknotes were introduced in denominations of 2, 5 and 10 dollars, with 20 dollar notes added on 24 October 1980. The first issues of banknotes depicted Queen Elizabeth II. However, all series issued later had the national crest instead. 50 dollar notes were introduced in 1986, followed by 100 dollar notes in 2006. A polymer two dollar banknote was issued in 2001 to replace the cotton fibre issue, but the banknote reverted to cotton in the 2006 series. The 2006 series also saw several new security features, including brighter background colours, a micro-printed holofoil on the 50 and 100 dollar notes, a tapered serial number, and a security thread woven through the note. On 26 September 2013 the Central Bank of the Solomon Islands issued a new 50-dollar note with hybrid security features by printers De La Rue, and announced it to be the first of a series of new banknotes over the course of five