All proof gold series are rare, but the Double Eagle is even more challenging to collect than the lower denominations. This is easy to understand when one thinks of the monetary value of $20 during the decades in which these large gold coins were struck. Few collectors could afford to purchase proof Double Eagles in the year of issue, and even fewer could afford to preserve these pieces in the long run. Indeed, many proof Double Eagles were later spent when their owners came upon rough financial times. Since the highest yearly mintage in the proof Type III Double Eagle series is only 158 pieces, one can easily understand the rarity of these coins in today's market. The most famous specimen strikings of this type are the proof-only 1883, 1884 and 1887, followed closely by the 1885 and 1886 due to the limited original mintages of the business strike '85-P and '86-P.