Unlike coins, the dates on US bills don't refer to the year in which the bill was printed. Instead it refers to a particular issue of bills having similar characteristics, called a "series".
To make things more confusing, the definition of what constitutes a series has changed over the years. At one time, a new series date was only used when there was a significant design change. When a new Secretary of the Treasury or US Treasurer took office, a small letter would be put under or beside the date; e.g. 1934 C - but even that was handled strangely. The first set of bills in each series are printed without a series letter, so an "A" would appear only when the first Secretary or Treasurer resigned. Thus "A" bills are really the second in the series, "B"s are the third, and so on!
Because bill designs didn't change during much of the 20th century, series letters ran quite high. For example the 1935 design of $1 silver certificate was printed up till 1965 and letters went all the way to H.
By the 1970s the Treasury had gradually adopted a policy of starting a new series based on the year that a Treasury Secretary was appointed, with a new letter added only when a new Treasurer took office. The practice of making "A" the second letter, etc. was continued though. As a result modern bills can usually be found with many different dates but series letters rarely go beyond B or C.
Unfortunately basing the series date on the Treasury Secretary in office during a given year has caused its own set of anomalies. For example, if a Treasurer holds their office for only a short time, some denominations may not be printed during that term so a letter may be missing. And bills with different designs may have the same series date if the same officials were in office. That happened when the old green/black $5 bills were superseded by the current purple and gray design. Both designs carry a series date of 2006, causing many people to conclude there had been some kind of printing error and sparking a lot of bogus rumors when in fact both bills were perfectly normal.
There were no series letters on 1988 US $100 bills. You may be looking at the Federal Reserve District letter. The series letter, if any, on US bills is next to the date. That said, modern-date $100 bills are generally only worth face value.
The last printing was in 1945. However these bills were issued as part of the 1934 series and they carried the series date 1934 A.
The last US $1000 bills were dated 1934, even though some were printed as late as 1945. In addition, there were no US bills of any type with the series date 1961. Please check the date and post a new, separate question with the bill's condition, date, and series letter (if it has one).
No. US bills are printed by "series" date regardless of the year when they're actually produced. As of 2015 the most recent series of $2 bills is dated 2013, although they were printed in 2014.
$100 bills were printed regularly throughout the decade, but because US bills carry a series date rather than a printing date it's very difficult to tell the exact year when a specific bill was printed. The 1928A series continued until 1934 when a new series was introduced. The 1934 series was printed until 1950.
The answer's a double no. First, bills aren't minted; they're printed. Only coins are minted. Second, there were no US bills of any denomination with a 1954 series date.
Check the date or rather series again. US dollar bills were not made in 1920.
Check the date or rather series again. US dollar bills were not made in 2010.
Check the date or rather series again. US dollar bills were not made in 1960.
The dates on US paper money are "series" dates rather than printing dates. A series date is changed when a new design is adopted; since 1974 the series date also changes when a new Treasury Secretary takes office. While it appears that no bills are printed during years in between series date changes, production actually continues with the original date regardless of the calendar year. In fact, because the 1935 series of $1 bills was never redesigned, they were printed into the early 1960s with that date!
The series-letter position on all US bills is either underneath or next to the date, depending on how much space the bill's design allows. However - - many bills don't have series letters. When a new series date is adopted, bills with that date are "plain"; i.e. they don't have series letters at first. If a new United States Treasurer is appointed (or, up to 1974, if a new Treasury Secretary took office as well) within that series date, a letter is added. That practice produces the strange notation where "A" indicates the second set of bills in a series, "B" is the third, and so on. Because there were multiple Treasury Secretaries and Treasurers during the 1957 series, they're found in 3 varieties - plain, A, and B.
No US bills were printed with a 1951 series date. Please check again and post a new question.