Going off the the two previous state added you mentioned. It possibly 46 and the 48 in 1912 then.
Yes, Arizona & New Mexico added in 1912 to take it from 46 to 48. Alaska & Hawaii were added in 1959
1787, Delaware, New Jersey, Pennsylvania
1788, Connecticut, Georgia, Maryland, Massachusetts, New Hampshire, New York, South Carolina, Virginia
1789, North Carolina
1790, Rhode Island
1791, Vermont
1792, Kentucky
1796, Tennessee
1803, Ohio
1812, Louisiana
1816, Indiana
1817, Mississippi
1818, Illinois
1819, Alabama
1820, Maine
1821, Missouri
1836, Arkansas
1837, Michigan
1845, Florida, Texas
1846, Iowa
1848, Wisconsin
1850, California
1858, Minnesota
1859, Oregon
1861, Kansas
1863, West Virginia
1864, Nevada
1867, Nebraska
1876, Colorado
1889, Montana
1889, North Dakota, South Dakota, Washington
1890, Idaho, Wyoming
1896, Utah
1907, Oklahoma
1912, Arizona, New Mexico
1959, Alaska, Hawaii