Even the most casual observer of the digital currency scene will be aware that 2017 was a record year in terms of performance. Obviously Bitcoin was the marquee attraction for new investors, as it should be given its incredible rise in December, but it was far from the only altcoin that had a banner year in 2017. Here are the top five non-Bitcoin cryptocurrencies of 2017 in terms of market capitalisation and percentage growth.How well did Ethereum do in 2017? Well, it managed to outperform Bitcoin by a factor of nine – how’s that for starters? Increasing its end-year value by a whopping 9,162% (compared to Bitcoin’s still impressive 1,000% return) Ethereum’s strength lies not only in its stability and its inherent value, but in the functionality of its blockchain that makes it a key choice for commercial developers.One of the cheaper altcoins per token (at the time of writing, a Ripple token will set you back a mere $2.05), Ripple had a hugely successful 2017, rising in value by 36,018% and achieving a market cap of just over $79 billion.Litecoin has made massive strides in 2017, increasing its market cap to over $13 billion, following a growth of over 5,000%. Part of its appeal is the quicker transaction times afforded by its blockchain, which makes it one to watch in 2018 as it stands a better chance of being adopted for trade outside of the altcoin scene.The new power coin on the block, Bitcoin Cash was only in existence for the last five months of 2017, but managed to accrue a market cap of more than $43 billion, which is no mean feat. It may the most carefully-watched coin since its more famous forebear.Chinese altcoin NEM uses a proof-of-importance system, rather than the traditional proof-of-work protocols, which has seen it attain a market cap of almost $13 billion. Whether any of these altcoins do as well in 2018 remains to be seen but, based on last year’s performance, they’ve got to be worth a look.